My work PC seems to have died but not in a way that I've ever encountered:

Nothing at all in terms of Video output
both HDDs seem to spin up
LAN card lights blinking

I assumed this meant that the VGA chip (on board) had died so I bought and installed a new graphics card

PC seems to boot up fine, HDDs spin up, CPU fan spins up but still no video

I've tried different monitors, connection types and cables

It's only a crappy PC but it seems a strange way to die

Any ideas?