Can U b more specific like Rating of PSU, name of the videocard etc.
I would first check to see whether my PSU has enough juice or not.
If I have any doubt on components like Hard Disk, RAM etc, Iwould try checking them on my friend's computer.
P4 1.6GHZ Willamette core 400MHZ FSB 256KB L2 cache
Intel 845WN Mobo
Nvidia Riva Tnt2 M64 G-card
40GB Seagate 5400rpm HDD
15 LG Studioworks563N
Creative Inspire2400 2.1 speakers
16x DVD ROM
52x Samsung CD Burner