Ok.
p4 are nice.
What are u trying to do with it? Games?
If your a gamer then u need to do alot to make it run fast. When the commurcials on tv say buy this p4 and play games at blazing speeds they are simply lieing at your face.
For games u need alot of memory, big hard drive, and graphics card wich u must buy seperatly and can be pricey.
Heres mine for example.
p4 1.3 , 400 front side bus - wich controls how fast everything goes along with proccesor, geforce 4 4600 ti - by Nvidia., 640 rdrambus ram. You prolly use ddr pc (####) somehting. And a western digital 7200rpm 80 gig hd with 5mb cash.
Sound confused? Its hard not knowing nothing about computer these days, youl go threw alot of bullcrap till i lurn how to make your own.
My suggestion if your completely computer iliterate is buy a cheapest one u can afford from here. www.alienware.com They are known but U pay for the name just like Dell. And dell sucks so dont go that route.
Make sure you get at least a p4 2.3 or higher for your money and a 533 fsp, but if u have the cash go 800. Get a 256ram video card, or get a 128 geforce 4 4400 or 4600 ti - Which are not bad.
Have at least a 80 gig HD.
A nice soundblaster soundcard. i use a audigy2 zs myself and its nice.
Duel dvd, cd-rom drives are nice incase one goes bad.
Another thing, how old s the comp. If its say 1 year old then its gettin alittle late to do upgrades without wasting your cash.
Sorry if this dont help u. But it shouldnt be slow IMO at a p4.
i have a problem in my computer. i have pentium 4 but the speed of my computer is not so good as pentium 4 have.
if any solution plz tell me.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic