ASUS P4S800D-X Hangs

[subodh_subu]

Hi,
I have a ASUS P4S800D-X ,P4 3.0Ghz MOBO, 1 GB(512 x2) Dual channel DDR 400 KINGMax Ram
My problem is sometimes when I do some hardware changes,for example something as simple as connecting a new monitor the the MOBO hangs .When I say it hangs i means it just shows the asus logo and nothing happens after that. The only way i could revive it is to take out the RAM and put it back again.Yesterday when i was connecting a different monitor (PC was OFF)it hung again. I cannot revive it again. I tried putting the RAM in all possible combinations,Resetted CMOS. It just wouldnt come up .I tried the RAM in another PC. It seems to be Okay. Do I have to get a new MOBO.
Any help would be appreciated.
Thanks in advance

 

[subodh_subu]

I removed everything from MOBO except the Display card and mem.No luck.. If I remove memory it will keep beeping and will not start .

 

[o1die]

Try using the cmos jumper while the power supply is unplugged, or remove the board battery for a few minutes.