|it's probably not a virus - a program designed to spread doesn't want to prevent your PC from booting; plus you'd at least be able to get to the BIOS...|
do you get the same behavior running off battery? AC with battery? AC without battery?
this definitely sounds hardware related, so if this machine is not under warranty you might be sol (unless you have a bunch of identical laptop components lying around, which is unlikely since every laptop is built proprietary).
my only advice is the next time you are able to bring it up, make sure your data is backed up to an external drive.