Question pc starts but monitor goes power saving mode[Done all POST error check and checked connections]

[Harrrdik18]

I was working on my old Pc and it stopped in between .So I restarted it didn't boot , monitor had gone to power saving mode But cpu fan was working and so was power supply .Then I did All POST error check and in last removing CMOS battery and fixing it again started my computer again ,It worked fine for like 30 minute till I tried to reset the time and date ,when I did that again it stopped .I thought problem might be with power supply but it seems to be working fine . Next time I again tried to reset BIOS by removing battery but this time it didn't work then tried a new battery that too didnt work So I performed CMOS jumper method and it started but than again I tried to reset my Time and date it again stopped.What you guys think might be the problem ?(Im really stuck for 2-3days)
My specs:
Intel dual core e5800
Gigabyte g41mts2
Ram 2gb (although I tried checking with different ram too but that didn't seem to be the problem)
No external graphic card
[I've rechecked all connections and they are properly connected]
Thanks in advance

 

[rgd1101]

how did you test the psu?

and stop reset time and date? could be the motherboard