Must be the day for boot up ERRORS. Mine is dead at the BIOS after attempting to exhange my 13 gb western for a 120 seagate, everything hooks the same but now after letting the Auto detect find the drive SUCCESSFULLY and saving the changes to a LARGE drive it will not get past boot up screen on my Acer open Pent III 550 w/ 640 mem. The del key will not take me back to the BIOS settings and the F10 key will not reset.  Any suggestions?I would First Try booting the computer with the Hard Drives Disconnected , and See if you can get in to the Bios.

Then if it worked i would Reattach the HDD but to a Different IDE Port

It may be you Bios just cant Handel a Large Disk

There should be a way to limit the Disk SIZE by using the Jumpers on the Back of the Disk , limit the Disk size and Try AgainThank you, the F10 and del still didn't get me in with the HHD disconnected. Not sure of the next step.  The Big Hammer maybe? I did try using the jumpers for Master drive designation and Large drive configuration when I could access the BIOS.  The auto finder said the three configurations were#1 Auto, no luck, #2 LBA, no luck, and #3 Normal, same results.  Now I'm broke.If you cant Get into your Bios with your Hard Drives Disconected , i think you may have a mother Board or CPU Problem.

Just to make sure , disconect Every thing thats not required to turn on the Computer.

IE : All i want you to have is PSU, Mother Board, CPU, key Board, and Maybe GFX card,
Only have these hooked up and try to get to bios

It might be Time To Head Down to the shops.