Bad Flash - now PC shuts down when trying to recover bios

Recommended by Wim's BIOS...

I messed up a flash on my MSI K8N Neo Platinum. I get the message that the bios is corrupt etc.

I've set up a boot disk and an autoexec.bat with the bios on, but about 3 or 4 seconds after accessing the floppy drive, the PC shuts off. I've tries different boot disks - still the same. It starts to read the disk, but then BAM - off again.

What can I do? I've tried tresetting the CMOS - no difference.
Have I completely messed it up?

[cp]

what are the contents of the autoexec.bat? did you put a flasher on the disk, too? is your bios an award or an ami bios?

It's an award bios. It shuts down whenever it starts to read ANY floppy - i tries with a Win 98 boot disk - same result. If I disconnect the floppy, it says error and shuts down anyway. If I can stop it shutting down I can get it to reflash the bios