PC random reboot,loading screen hang on vista

Hello i have a problem in my pc and im out of solutions to try
I have:
mobo: X58 platinum
cpu: i7 core 920 cpu
psu: 850W Chieftec
gpu: EVGA geforce gtx 280
ram: 4gb DDR3
hdd: caviar black 1TB
and running windows vista 64-bit

The problem is that i have random reboots at no specific time or task running and after the reboot usually the system hangs when starting windows at loading bar for about 30sec and after that it loads ok..
I have looked at temperatures and everything seems ok, cpu at ~30 c ,gpu ~53 c also i had the same isue with my old hard drive but it didnt fix after changing to my new one..
the only thing that i find strange is that on boot pc makes strange beep noices (2 or 3) ( i have plugged in a speaker from my old mobo since this one did include any) but system runs gr8 generaly
I have the latest drivers on everything..I run memory diagnostic tool with no errors and have scanned the hdd for errors also..i really dont know what else to do any help would be appreciated