Thee are many things that u can do.. but i advice a few easy ones.
Perform an Disk Cleanup : Start -> Programs -> (Not sure, u have to search)Tools And Extras -> System.. -> Disc Cleanup.
Go To Your Documents and delete everything that u don't Use.
Also, go to ''My Computer -> Harddrive : C -> Program Files , delete the Programs that you already uninstalled.
Now go to Start -> Control Panel -> Ad/Remove Software and delete the apps that you don't use. Now for your computer faster..
Go to Start -> Run, type : msconfig Press Enter.
You get a screen, at that screen go to the tab ''Startup'' and there can you put apps that have to load at the startup of your computer.
You have also apps like Xp Tools, for a proper disccleaner. You can download a Trial Version.
http://www.xptools.net/
Good Luck !!
.Giorgo.