How long did Memtest86+ run? You should run it for at least a night ;-)
Is there a bios update available for this computer?
Did you tamper with any bios settings?
Try to load bios (safe) defaults and then try to disable all cashes or shadow ram.
It sounds like some sort of corruption. It is trying to load the kernel and since this failes there is nothing else to do.
Did you check the drive for errors?
smartctl -a /dev/hda
Did you try to install it again?