It shouldn't make any difference - it will just free up space on your hard drive, which is nothing to do with RAM.
But it won't do any harm if you are sure you don't want the programmes any more.
To make your pc run faster:
1. Clear cookies, caches and temporary files. This free programme is excellent:
http://www.stevengould.org/software/cleanup/
2. Defrag your hard drive. Start - Control Panel - Performance&Maintenance - rearrange items.
3. Stop programs loading automatically when you start the pc. Many automatically put themselves in the startup folder, and you may not use them at all that day. This uses resources unnecessarily. This free program, Startup Inspector, makes it easy:
http://www.windowsstartup.com/
You should see an improvement, especially if you don't defrag regularly.