DVI Ports not Recognised

I have 2 computers linked by a Belkin KVM. Everything was working fine until yesterday. I booted up PC 2 and the POST screen came up but just when it was about to show the Windows log in screen, the monitor displayed no signal. The graphics card has a HDMI cable connected to my TV and that is working, just none of the 2 DVI ports.

This happened a while ago and I ended up reinstalling Windows which solved the problem but I'm hoping to avoid doing that this time and actually fixing the problem.

The monitor is definitely working as I'm typing this using PC 1.

I've uninstalled and reinstalled the graphics card. Driver is up to date so I'm out of ideas. It's strange the HDMI port works but neither DVI port is detected

Any suggestions?

UPDATE: I ran the AMD cleanup utility to totally remove all the software. When the PC rebooted, the monitor was working, just low res.

I installed the Radeon software again, the screen went blank and made the noise like it found new hardware. The TV came back on but the monitor showed no signal again.

So the problem is with the Radeon software

UPDATE 2: I ran the AMD clean up utility again but this time I let Windows update install the graphics software. Same problem. HDMI to TV works but DVI ports are not recognised

You can also use DDU download ddu to clean up old drivers with no residue at all.

Removing the software is not an issue. The problem is that when the display adapter driver is installed, the DVI ports stop working.

So I went ahead and reset the PC. Everything was working so I plugged in the HDMI cable. No signal on the TV.

I took the cable out of the graphics card and plugged it into the onboard HDMI port. Enabled multi-monitor in the BIOS and everything is working.

I just can't update the drivers for the onboard graphics or the graphics card because when I do, no signal.