Increase your PC's RAM!!

Use Ready Boost to use your USB as a temporary memory to increase your RAM.
Do chek this link...

http://www.sevenforums.com/tutorials/33289-readyboost-setup-use.html

Windows boots up Slow..Cool Solution??

1)goto run-->msconfig...and remove the items from startup which eat up your memory while startup but you don't need them as such.

2)Delete all temporary files from your Windows machine..
goto run-->%temp% and delete all temporary files.

I hope your computer is not infected else you need an antivirus first!! :)