Hi,
Compaq Presario V6000 are known for a big hardware problems with the GPU and the Mainboard.
I have one, my laptop still have a black screen when booting... nothing on the screen.
So I took the mainboard, remove CPU, RAM, and remove any plastic item ( eveything you know it can melt )... And put the mainboard in the oven ( at 160°C ) for 3 minutes.
When 3 min past, be careful, handle the mainboard carefully. Put in on your table.
Wait until the mainboard is cool.
Replace the mainboard carefully.
=> Test