Asus m2n-e sli locks up at bios post splash screen

Try reseating the power cable to your HDD and also the data cable to and from your motherboard. If no joy - then it sounds to me like a power supply unit failure

Accordin to manual: Error Code – 50

Phoenix (50)Display CPU type and speed.(Beep)=2-2-1-1.(50)Per- form LSL instruction test.[Beep]=none Custom chip set or custom platform.

The POST process stop detecting CPU.

M2N-E SLI use Award/Phoenix BIOS.

The POST error message (beep codes) indicated the BIOS/CMOS battery is flat and needs to be replaced.

Hey, I own the same motherboard and I don't have your problem.
I would suggest trying to update the bios, i think its more of a bios problem / motherboard issue, not windows related.

you can get the newest bios from http://support.asus.com/

I have the same board (M2N-SLI) with a BFG 9800 GTX with no video either. I have the card in the black slot and I have 2 mem sticks in the yellow. Shouldn't make a difference if I'm using a monitor not an LCD right? Everything spins up for me too, hard drive, vid card has power, CPU fan is on, post (green) light is on.

Are you sure that the memory you have installed is compatible with your motherboard.

It is weired but some memory do not work with certain motherboards, irespective of speed or voltage rating.

That single beep is most likely POST. Power on self test. You're board, Asus M2N-E SLI uses an Award bios. The beep error codes can be found at this link: http://www.bioscentral.com/beepcodes/awardbeep.htm
If you are using a single PCI-E card, check that you have the bios set correctly. Shown on page 4.4.6. Do you have you're memory in slot A-1 & A-2? Check that you have PCI-E set for primary display adapter, pg 4.4.4
For windows XP Pro with out SP2, please disale ACPI in you're bios. After SP2 & updates, you can turn it back on. It's realy odd that you're high power PSU did not come with an ATX 4-pin_12v connector for the board. (Needed for CPU).
This is a standard feature for current PSU's. Can you swap the PSU? Considering what devices you are running. You can easely run a 350w PSU? This swap would only be used as a test. Next test, go into the bios & go to Advanced, CPU configuration, check hardware monitor. Stay here a bit & watch temp settings.

Go over these suggestions. Let me know if any one of these suggestions has helped? Can you see the drive in you're bios?

Luck!
M

You will need to pay close attention to how many beeps & if their short or long. Asus uses the Award BIOS. Beeps are a part of POST. Power On Self Test. Open the link below to find out what your beeps mean.
http://www.bioscentral.com/beepcodes/awardbeep.htm

I could not find BIOS ver. 1302 for the M2N-E Mb. What I do know: Your dual core 4200 showing up as "unknown". Asus says:
This is because the BIOS does not have the relative CPU uCode to support this processor. Please simply update your BIOS to version 0902 or later to resolve this problem.
BIOS 0902 can be downloaded from the link below:
http://dlsvr01.asus.com/pub/ASUS/mb/socketAM2/M2N-E%20SLI/0902.zip
Once you cpu shows up correctly, chances are that your over clocking will work and the bios will stop sending you back to change your settings.

did you install the motherboard drivers using the CD which came with it?