I have a complicated problem. I was trying to make a multi-boot drive but I was having a problem loading a real old form of excel. I thought it was the hyper threading so I went into the BIOS and switched it off but the problem really was that this old excel was using the old FAt32 memory allocation. I figured that out later. So stymied at what I was attempting I decided to load up the original operating system, mind you, my hard drive has been completely formatted at this point. So it starts to load and just at the point where it shuts down before it comes back to load the operating system I remembered I had forgotten to switch on the hyper threading. Too late, it boots up but only half way and I can't get back into my BIOS because F2, F8, and F12 won't come up, neither will it take a boot disk or any other kind of operating disk. What to do? I'm on a library computer so I'll have to check back over the next four days to see if anyone knows a solution. Thanks Mike.
Did you try to boot with the HD removed? You should be able to enter and change the BIOS. You might also try to download and burn a CD with a bootable OS utility that allows you to repartition and format your HD.