Why Is My Computer Running Slow

I’ve unchecked all unnecessary programs from the start-up (Run > msconfig > Startup). I’ve uninstalled every program I haven’t used in over 2 months. And I’ve defragmented.

Still, my computer is very, very slow immediately after the start-up; it takes about 15 minutes after booting up the computer for everything to work normally. Usually, if I try to even open the My Documents folder, it lags and takes forever to load up.

Should I re-install my whole computer or should I do something else?

dbmethod.com Did you just install windows xp and find something is not working right?