Cannot say I've ever seen this before. I have a laptop here that boots to the POST screen, I can go into BIOS menus, etc. but as soon as I try to boot from the hard drive, cd-rom drive or floppy drive I get a blank screen. Everything looks good in the BIOS menus... all driver recognized... I tried resetting to defaults... no change.
This laptop has had, and is still having, problems with the ac-jack... it needs to be re-soldered. If I hold it at the right angle... I get power. So maybe a short developed at a time and excess voltage caused a problem.
Anyways... never seen this before. Corrupt BIOS-ROM? Isn't that typically an all or nothing thing?
I've tried external monitor... no luck there.