Dual Boot System Win98/Win NT 4,SP6a

I have a P-III 700Mhz,Intel 810 Chipset machine running dual boot with Win98 and Wint NT 4;SP6a [64 MB RAM],sometimes while working on Win NT my system suddenly starts dumping physical memory and then reboots.No such problem with Win98.Please tell me what is the problem,i have contacted my machine’s vendor he says it the motherboard i.e Intel 810 Chipset needs to changed to a powerfull server motherboard.Please advise what should i do?