I have this Asus p7p55d-e pro for about 8 months(got it last July) and for this last 3-4 days I cannot boot without clearing my CMOS

what I have is:

Seasonic M12D 750W
ASUS P7P55D-E Pro
Intel Core i5 760 Quad Core Processor Lynnfield LGA1156
XFX GeForce® 8800 GT Alpha Dog 512MB DDR3 Standard (PV-T88P-YDF4)
2x Corsair XMS3 CMX4GX3M2A1600C7 4GB DDR3 2X2GB DDR3-1600 CL 7-8-7-20

I tried to remove all the unnecessary stuff: HD/dvd/pci card/usb cable/etc

I tried with only 1 dimm filled, instead of my 4, each one individually

it didn't work

I tried changing the battery, here goes a few dollars to nowhere, didn't work

if I don't reset the CMOS it sometime stock on RAM led, sometime on BOOT DEVICE led, when this happen, it stuck on CPU speed detection

when I boot right after the reset, i MUST click on the F2 option (boot with default bios setting) if i go into the bios and save/restart, i have to reset it again

when booted, everything is rock solid stable, tried memtest, cpu stress, etc, etc. without issue

what should be my next step? trying a new psu? (i need to find one..) doing rma? (i need this mb since it's my only computer...)

something else?