UBUNTU - Ubuntu is an operating system built by a worldwide team of expert developers. It contains all the applications you need: a web browser, office suite, media apps, instant messaging and much more.

Ubuntu is an open-source alternative to Windows and Office.

http://www.ubuntu.com/

OpenSolaris - The OpenSolaris Operating System offers unique features designed to help you build and deploy high-performance application services, starting with the Image Packaging System (IPS), continuing to the latest enhancements to the award-winning ZFS and featuring integrated virtualizaton options that span OS, network and storage - and that's just the beginning. OpenSolaris gives you next generation Solaris technologies coupled with the best in open source software and a vibrant development community. 

http://www.sun.com/

Slax - Slax is a modern, portable, small and fast Linux operating system with a modular approach and outstanding design. Despite its small size, Slax provides a wide collection of pre-installed software for daily use, including a well organized graphical user interface and useful recovery tools for system administrators.

The modular approach gives you the ability to include any other software in Slax easily. If you're missing your favourite text editor, networking tool or game, simply download a module with the software and copy it to Slax, no need to install, no need to configure.

If you are a beginner or you're just too busy to make it yourself, follow a few steps to build your own customized operating system by using web-based interface.

http://www.slax.org/

OpenOffice.org - OpenOffice.org is the leading open-source office software suite for word processing, spreadsheets, presentations, graphics, databases and more. It is available in many languages and works on all common computers. It stores all your data in an international open standard format and can also read and write files from other common office software packages. It can be downloaded and used completely free of charge for any purpose.

http://openoffice.org/

AbiWord - AbiWord is a free word processing program similar to Microsoft® Word. It is suitable for a wide variety of word processing tasks.

http://www.abisource.com/

GNUMERIC - The Gnumeric spreadsheet is part of the GNOME desktop environment: a project to create a free, user friendly desktop environment.

The goal of Gnumeric is to be the best possible spreadsheet. We are not attempting to clone existing applications. However, Gnumeric can read files saved with other spreadsheets and we offer a customizable feel that attempts to minimize the costs of transition. 

http://projects.gnome.org/gnumeric/

GIMP - GIMP is the GNU Image Manipulation Program. It is a freely distributed piece of software for such tasks as photo retouching, image composition and image authoring. It works on many operating systems, in many languages.

http://www.gimp.org/

INKSCAPE - An Open Source vector graphics editor, with capabilities similar to Illustrator, CorelDraw, or Xara X, using the W3C standard Scalable Vector Graphics (SVG) file format.

Inkscape supports many advanced SVG features (markers, clones, alpha blending, etc.) and great care is taken in designing a streamlined interface. It is very easy to edit nodes, perform complex path operations, trace bitmaps and much more. We also aim to maintain a thriving user and developer community by using open, community-oriented development.

http://www.inkscape.org/

CCleaner - CCleaner is a freeware system optimization, privacy and cleaning tool. It removes unused files from your system - allowing Windows to run faster and freeing up valuable hard disk space. It also cleans traces of your online activities such as your Internet history. Additionally it contains a fully featured registry cleaner. But the best part is that it's fast (normally taking less than a second to run) and contains NO Spyware or Adware! 

http://www.piriform.com/ccleaner

Advanced SystemCare Free - Advanced SystemCare Free (formerly Advanced WindowsCare Personal) has a one-click approach to help protect, repair, clean, and optimize your PC. With over 35 MILLION downloads since 2006, this fantastic, award-winning free registry cleaner and system optimizer is a "must-have" tool to speed up your slow computer. 100% safe with no adware, spyware, or viruses; a PC maintenance program that’s incredibly easy to use. 

http://iobit.com/

Revo Uninstaller - Revo Uninstaller helps you to uninstall software and remove unwanted programs installed on your computer even if you have problems uninstalling and cannot uninstall them from "Windows Add or Remove Programs" control panel applet.

Revo Uninstaller is a much faster and more powerful alternative to "Windows Add or Remove Programs" applet!

With its advanced and fast algorithm, Revo Uninstaller analyzes an application's data before uninstall and scans after you uninstall an application. After the program's regular uninstaller runs, you can remove additional unnecessary files, folders and registry keys that are usually left over on your computer.

http://www.revouninstaller.com/

Your Cleaner - Your Cleaner is a free maintenance program that promises to rid your systems of unwanted files. It's not the prettiest program to look at, but it quickly and successfully removed all selected files from our system. 

http://yourcleaner.ucoz.net/

Defraggler - Use Defraggler to defrag your entire hard drive, or individual files - unique in the industry. This compact and portable Windows application supports NTFS and FAT32 file systems.

http://www.piriform.com/defraggler

Recuva - Accidentally deleted an important file? Lost something important when your computer crashed? No problem! Recuva recovers files deleted from your Windows computer, Recycle Bin, digital camera card, or MP3 player. And it's free!

http://www.piriform.com/recuva

A9CAD - Very useful program for people familiar with Autocad. Opening and editing Autodesk files is a seamless process. Moreover the general user interface, program logic and commands are modelled on the most popular cad solutions. A9CAD is an excellent ACAD-compatible program for the occasional CAD user. With all the functionalities A9CAD could do everything I wanted and more.

http://www.a9tech.com/

XnView- XnView is a free software to view, organise, convert graphics and photos files or to create slide show, contact sheet, HTML pages.

http://www.xnview.com/

Wise Registry Cleaner - Wise Registry Cleaner free is a powerful free registry cleaner and registry optimizer, it speeds up your PC by cleaning your Windows Registry. The PRO version help you improve your PC's performance by optimize your Windows Registry, and it's so easy, you only need make a few clicks. 

 Wise Registry Cleaner will make your Windows computer faster and more stable. It removes the junk that accumulates in your Windows Registry. You can safely and easily clean your Windows registry.

http://www.wisecleaner.net/

Wise Disk Cleaner - By cleaning your disk with Wise Disk Cleaner, your computer will run faster, and you won't have to worry as much about filling your hard drive and replacing it with a newer, bigger one.

Wise Disk Cleaner is a user friendly, fast and easy to use application developed to free up disk space by deleting junk files that are no longer used by any software on your system. Even the least experienced user can easily remove junk files with this tool.

74% of discarded PC hard drives contain private data that can be easily read and recovered... even if the drive has been reformatted. Disk Scrubber of Wise Disk Cleaner will help you permanently to wipe deleted files for keep your private. 

http://www.wisecleaner.net/

AVG - With AVG software on your system, you can safely surf the net, create online profiles, shop, bank online, download files, store data, chat, and email, safe in the knowledge that your personal and professional information will not be stolen or misused.

http://free.avg.com/ww-en/homepage

PDF XChange Viewer - The PDF-XChange Viewer is designed to create PDF files only from images - or to scan new pages from your scanner - as well as View/Modify/Annotate etc - existing PDF files.

http://www.docu-track.com/

Quick Zip - Allow you to perform powerful archive operations over a wide range of archive types using a familiar explorer like interface.

http://www.quickzip.org/

Universal Viewer - Universal Viewer is an advanced file viewer with wide range of formats supported. Implemented view modes and corresponding file formats are: 

Text, Binary, Hex, Unicode: any files, of unlimited size (even 4Gb+ sizes are allowed);

RTF, UTF-8: RTF and UTF-8 encoded texts;

Image: all general graphics formats: BMP JPG GIF PNG TGA TIFF... plus all formats supported by IrfanView/XnView external viewers;

Multimedia: all formats supported by MS Windows Media Player: AVI MPG WMV MP3...

Internet: all formats supported by MS Internet Explorer: HTML PDF XML MHT...

Plugins: all formats supported by Total Commander Lister plugins;

MS Office: all file types of MS Office (if installed): DOC DOCX XLS PPT...

Converters: some types can be viewed as plain text: DOC DOCX PDF PPT ODT...

http://atorg.net.ru/

Era Password Manager - Era Password Manager is created specially to relieve computer users of headaches about lost passwords, typing usernames, passwords and storing securely valuable information.

If you are fed up with forgetting your passwords or having to keep writing them down then it's time to get Era Password Manager. From now on the only password you will need to remember is the one you assign to Era Password Manager itself.

http://www.dheone.com/

BSplayer Free - BSplayer Free is used by more than 70 millions of users throughout the world and it has been translated into more than 90 languages. All the downloaded versions of their free player surpass the sum of all downloads of competitive video players and payable DVD players. Because it does not use much processing power it is suitable for all those who use slightly less capable computers but still want to have excellent video and audio quality. The multimedia playback has not been – and never will be – disturbed by any annoying technical problem, much too often experienced with software of this kind. 

http://www.bsplayer.org/

Mozilla Firefox - The award-winning Firefox Web browser has security, speed and new features that will change the way you use the Web. Don’t settle for anything less.

http://www.mozilla.com/

Opera - Opera is a fast and secure Web browser from the most innovative browser company. Opera allows you to download and run Web applications and to share content with others in a quick and easy way.  

http://www.opera.com/

Netscape - When you use Netscape® Search with Google™, you search less and discover more. This product delivers comprehensive web results from Google along with One Click access to relevant videos, pictures, local maps, news, stock quotes and more.

http://netscape.aol.com/

Skype - You can chat away with free Skype-to-Skype calls and never worry about cost, time or distance. Share the love and get your friends to download Skype so you can talk, instant message (IM) or make video calls for nothing. You can also make calls to phones and mobiles at home and abroad at great rates too.

http://www.skype.com/

Free software links:

http://alternatives.rzero.com/

http://www.webg.org/

http://freesoft.start.bg/

http://www.virusdefence.org/

http://skss.learnfree.eu/

http://www.myfreesoft.net/

http://antivirus.one-bg.com/

http://www.softvisia.com/