Hello. my PC have been rebooting lately and when i check Even Viewer/ System there are no errors and only Save Dump. there are may be two reboots per week so its not a big problem but i'd like to know what is causing by PC to reboot unexpectedly. eMachines T3418 AMD Athlon 3700+ 2.4 GHz Clawhammer ( used to be Sempron 3400+ but i upgraded that to this) Mobo: K8MC51G RAM: 2 gigs of DDR 333 PC 2700 OCZ (3-4-4-7 timings) GPU: Ge Force 7900 GT 256 MB PSU: Thermaltake Purepower 500 Watts ( used to be crappy one from emachine's, i upgraded it to this one) OS: Windows XP home edition SP3 Avast! antivirus 160 gig Seagate Barracuda 7200 RPM 8 mb cache Thanks a lot in advance. i would really appreciate some help.