Hi all,

I was trying to help a frien out with her pc. I scanned her hard disk by
slaving her hard disk to mine and found 4,000 viruses. When I returned her
hard disk to her pc and tried to boot up, got this message on the monitor
"Self Test Check your pc and signal cable Monitor is working". Though I can see the CPU fan spinning and hard disk humming and the cpu lights blinking,
no image comes out of the screen. Can anyone please advise? Thanks.

Two possible causes:

1. You forgot to plug the monitor cable back into the graphics card output on the base unit.

2. The graphics card has become slightly dislodged. Remove the graphics card from the motherboard, check that there isn't a lot of dust in and around the slot and then push the graphics card back into the slot, carefully but firmly. You should ensure that the contact edge is completely seated within the slot as evenly as possible (i.e. not pushed in at one end but sticking out at the other end).

Let us know if that does or doesn't help