Booting problems!!Please help!!!

[Amitava83]

INTEL C2D E7300 2.66 GHz
MSI P7NGM DIGITAL Motherboard
Palit Radeon HD 4870 SONIC 1GB Dual Edition (with dual bios)
Seagate Barracuda 7200.11 HDD 320 GB
Corsair 2X2 GB 800MHz RAM
Cooler Master eXtreme Power 600W PSU with 70% efficiency
Cooler Master CM 690 Cabinet
Dell E1909 W 19" LCD
Liebert Emerson 600VA UPS

I installed XP SP2 and Vista with SP1.From the very first day,whenever I switch on my PC,the motherboard logo flashes on screen and then a strange beep of about 3 seconds comes from the cabinet and immediately after that the system hangs completely.I reinserted the RAM several times but the problem persists.The strange thing is when I restart my PC,it still gives me that strange sound but it boots properly and I can login into both XP and Vista and even can play Crysis at very high resolution for 10 hours at a stretch without any problems.

I would like to mention here that my huge graphics card has physically covered almost all the six SATA ports on my motherboard and the HDD SATA port was connected with very much difficulty.I even had to keep the entire cabinet in a lying down position as in the upright position my graphics card literally throws its whole weight on the HDD SATA port below .

Is my particular motherboard incompatible with my Graphics card?Or otherwise,is my SMPS not powerful enough?The box for the Graphics card says it alone needs 500W Power Supply.

I'm utterly confused and losing my sleep.My appeal to all the guys out there please please help me with your suggestions.

[realdan]

try with either of ram stick one by one
repeating it in different slot

[topgear]

1. Check with different Rams.

2. Re-Insert & Re screw the gfx card firmly with cabby. It should stick firmly with your cabby - I think loose gfx card connection is the main prob here.
Also if possible check wuth a different gfx card.

As I've faced this kind of prob ( loose connection with mobo ) with my AGP ( 5200 ) gfx card.

& Plese don't make 2 threads for same issue