Good advice there...
Also make sure that no software is set to 'auto-update' like your Anti-virus definitions, or any media players etc etc...
And go into scheduled tasks and disable all the scheduled tasks (you can always run these when YOU want... windows has this annoying habit of doing stuff at the wrong times unless you change the settings)
Lastly press control-alt-delete and see what is running in the background... you can also goto the start menu-run then type msconfig and disable as much stuff as you want from loading when you boot up, be careful not to disable stuff that you're unfamiliar with or it may have adverse effects... alot of stuff is safe to disabe tho...
All these little things should help.