Abit IP35 Pro won't boot with 4 sticks, help

it used to work fine until i restarted today and now it won't boot with 4 sticks anymore. at first i thought one of the sticks went bad, but i don't think thats the case, because i have tried all of them individually and the system boots each time. when i have all 4 sticks in the mobo displays a post code of 'C5' which the manual says is "Call chipset hook to copy BIOS back to E000 & F000 shadow RAM" whatever that means. so i took out the stick out of the fourth slot and it booted again, and then i thought it was that slot on the mobo that went bad. then i tried just the fourth slot on it's own and it booted again. at this point i'm going insane..... so i tried slot 2 and 4 at the same time and i get a 'C1' code on the mobo and get long beeps, manual description "Detect memory
-Auto-detection of DRAM size, type and ECC
-Auto-detection of L2 cache (socket 7 or below)."

Any ideas on what's wrong, is my mobo dead?

if your mobo was dead then it wouldnt work at all... try removing the cmos battery for a 1hr or longer, with cmos switch flips to the reset position. then after the hr put the battery back in and try agian. i do suggest setting voltages and cas timeing first with one stick then adding the others. my board is doing just fine with 4 dimms populated....

another thing just because each stick boots fine still doesnt mean they are fine. run memtest86 on them, get the ISO so it boots from CD. very handy to have for figuring out if its the ram or not.

Check out the Abit forums. There are a couple people that are really helpful with this board.

I had the very same problem with my old Abit F190HD. I left the board overnight and it just worked again. I think resetting the CMOS and Updating the bios/reflashing the bios would be your best bet.

Also, you may need to up your NB voltage a tiny bit. -Maybe its even the case that the boad is putting to tight timings on each chip.