Click start type in regedit and click the program. Click HKEY_current_user, then software, then microsoft, then windows, then current version. After that scroll down to run and run once, delete everything in both Run and Run Once that is not needed.
yeh like djstu45 said use ccleaner to clean up your registry as its pretty hard to break anything with it and do a defrag if you can after you might want to try a program called tweak VI (if your on vista) or tweak ui (xp)there is a one for 7 but I cant remember what its called right now these have some good options for increasing performance you can also try increasing the size of your page file which is a section of hard drive memory that your pc uses as ram you need to go into control panel then system then click on advanced system settings then click on performance click the tab that says advanced and then click what it says on virtual memory how much you add is up to you but try and find a good balance between the space on your hard drive and the amount you assign the file( that's to change it on vista xp is pretty similar but I cant remember the exact details just google increase xp page file size and you'll find a tut.
hope this helps
oh and if all else fails you can always install more ram memory its cheap enough now and is very easy to install
Get more RAM. You have only have 704 MB, this means that your CPU is trying to store some things that it commonly uses but you simply don't have enough RAM to hold everything that the CPU wants. That's why programs are being slow.