Unable to playback video, suggestions?

Hi all...

I've run into an odd problem whereby I cannot get video to playback any longer. I've been successfully running Resolve for several versions and have not changed any hardware/software other than updates/drivers for some time.

When I open an older project or create a new one with known good video files, neither the Edit screen or Cut screen allow the clip to playback, it simply does nothing.

So far in attempts to resolve, I've:-

Performed a factory reset of the AMD Radeon software v20.11.2

Performed an update of the Radeon RX580 drivers

Uninstalled Resolve v17

Reinstalled Resolve v17.1

Checked Resolve Preferences/Memory & GPU/OpenCL & Radeon selected

Confirmed video clip playback on PC via other software

I'm at a loss for other things to try which is why I'm here annoying you experts.

Any assistance appreciated!

Simon