Strange major problem with 975X PowerUp Intel MOBO

Question

I’m suddenly having a strange major problem with a MSI 975X Platinum PowerUP Edition V2.1 MS-7246 Intel socket 775 motherboard. Previously, it had given me no problems at all.
It went like this:
Powered on system in the morning, booting from a cold start.
Hit DEL key to get into the BIOS.
Missed the window and the system booted into Windows normally.
Re-started the system from within Windows.
Hit DEL key to get into the BIOS and was successful the second time.
Hit the ENTER key on the first item “Standard CMOS Features”.
The DATE, TIME and other information was displayed on the next screen, but at this point, the BIOS screen became completely unresponsive to any keyboard input.
The only thing I could do at that point was to power off.
Subsequent power on boot-ups resulted in the system always freezing at the BIOS splash screen after the video card sign-on.
I have switched power supplies, hard drives, keyboards and video cards. I have disconnected everything except the video card, keyboard and one RAM module. I have switched the four RAM modules around and then reduced the RAM to one 256MB module in the proper slot. I even changed the battery on the MOBO, in case it had shorted out and removed and re-seated the BIOS chip. It still halts at the BIOS splash screen.
The BIOS chip can’t be completely dead, because I powered off and pushed the BIOS reset button on the MOBO to reset the BIOS to the factory defaults. When I re-booted, I could tell that it had actually reset to the factory defaults because I had previously set the BIOS to reboot the system on resumption of power and the factory default was to remain off until the power button was pushed, which was now the default.
I’m stumped! All I can think of is to get a new pre-programmed BIOS chip and see if that makes any difference, but I’m not sure this system is even worth the expense with no guarantee of success. Any suggestions on how I might get past the BIOS splash screen or do I for sure have a corrupt BIOS chip?

Answer 1

System specs as per the posting guidelines -
Board: MSI 975X Platinum PowerUP Edition V2.1 MS-7246 Intel socket 775
Bios: Version (can’t recall & can’t check since it won’t go past the BIOS splash screen)
VGA: ASUS EN7600GS nVidia GeForce 7600GS PCI-e 256MB DDR2 (also tried new XFX nVidia
         Geforce 210 PCI-e 2.0 512MB DDR3)
PSU: Chiefmax 680W ATX (also tried new OCZ 700W ATX)
CPU: Intel 2.8GHz LGA-775 Core2 Duo Dual-Core Processor
MEM: 4 x Samsung 512MB 1Rx8 PC2-5300U (2GB total)
HDD: Seagate Barracuda 250GB SATA2 (also tried Seagate Barracuda 500GB SATA2)
COOLER: Intel OEM LGA 775 fan/heatsink C25897-001
OC: No
OS: Vista Home Premium 32-bit
I have been through the BIOS reset procedure several times and pretty much as outlined. As I said before, I could tell that it had taken a reset to the factory defaults, because the power on option had changed.