check out the number of setrvices currently runnin on ur computer and disable those dat u donot need
u can access d services window
Start->Run->Services.msc[Enter]
u cud check out a few sites
WINDOWS XP SHUTDOWN & RESTART TROUBLESHOOTING
Shutdown is very slow - Windows XP
A nifty tool dat will disable magjority of the unnecessary services is
GameXP
altho it will leave out a few services which i find unecessary, i let it fisrt do d job b4 i clse down additional services myself, save time