[entwisi]

The Nvidia screen is just a GFx chip POST, nowt to worry about.

The error about system disk suggests that your HD has either a) died or b) lost it master boot record. The latter could be due to many reasons from virus infection, or something as simple as a bad sector. you need to get hold of a LiveCD and boot from that, you can then try to access the HD. If it can then its MBR thats screwed. You can fix this by using "fdisk /mbr" or by installing a new boot sector from something like a linux CD/DVD. If a linux livecd can't access teh HD its knackered