check for your recently installed softwares, minsan nag cconflicts sa system mo.
marami factor kung bakit nag ccrash, try to reinsert your mem (minsan nag eeratic yang mga yan, and ddr 133? wala yan, prolly your refering sa sd mem) or even videocards, try reinsert, as long na may nakikita ka sa monitor, its not the hardware, unless your playing quake 4 on a 1.7ghz, mahihirapan, but still it doesnt auto reset your pc, mag hhang lng.
and you ishimaro, how come celeron class are not reliable when comes to games? 2.6ghz are fair speed for processing, yes, we all know p4 are much faster than celeron simple bcoz there differ from bustype.
why blame the poor celeron, 3d games are dependent on vidcards. and for his case its not the cpu that has a problm.