Motherboard: ASUS M4A785TD-V EVO
CPU: AMD Athlon II X4 620
RAM: GEIL DDR3 1333 RAM CL7-7-7
Well, I was installing a new CPU cooler I bought, mainly a VERY large one. Took it apart, reassembled with the new cooler (had to take motherboard out to put on backplate, you know how it is) everything seemed fine in the build phase.
Turned on the computer and was welcomed by RAMPANT problems. My operating system Windows 7 would BSOD with the "Memory Management" error. Fixed this by taking one of my 2 2GB sticks out leaving me with one.
Before this all happened my RAM worked perfectly fine, so I am guessing I messed something up during installation or I dont even know, so I am asking you nice folks.
Also, my BIOS does not let me make any changes whatsoever. If I change something (i.e. overclock my CPU) and click "exit and save changes" it will not beep and sit at a black screen when it exits BIOS. No idea what that's about.
Hopefully this isn't the case, but did you take static electricity precautions when working inside the system? Wrist strap? If not, did you remember to touch a bare metal part of the case occassionally? Also, It's best to leave your PSU plugged in to a grounded outlet when working on your system. Always turn the PSU off, of course. That way any static discharge will flow to earth.
You may want to try resetting your BIOS by removing the CMOS battery and jumpering the 'Clear Cmos' pins on the board (pg. 1-18 in the manual) for a few seconds to discharge the caps and reset the BIOS to factory.
I always make sure to touch the case every ~half minute. My family say I am too paranoid in that respect but never can be too careful. Good to know on the power supply still being plugged in thing though.
I will try removing the battery itself, I did clear the CMOS with the pins, but didn't do much of anything.
You may also want to boot to "Memtest" and run a test on each stick of memory alone to see if each stick is OK. One complete pass per stick should be enough to tell. http://www.memtest86.com/download.html