thank you all for the replies.....in haste i have handed over the PC to computer service technicians

....as for config: amd XP 2400 processor...MB: Asus A7V8X MX SE....VC: Nvidia 6600 GT AGP 8X 128MB.....as for problem with ram.....have DDR 226 Mhz 256 MB+ 512 MB....while testing with either one remaining on board, the system continued to crash....i concur with Beta Waves, ashutosh.sanny, RexRazr that it is in all likelihood a driver problem....BTW are MBs with AGP slots still available in India? and Are PCIe+AGP DUAL slots MB too available? and if, yes, place(s) where I can get them?