Blank (black) screen for all modes except Coherence after Parallels for Mac upgrade

I recently upgraded to Parallels Desktop for Mac 8.0.18314, and had been using the version just prior to this with Windows 7 64-bit edition with no problems.

I usually work in Full Screen mode and during the first boot following the PD upgrade, the boot process looked normal, but as soon as the Desktop would normally appear, I would hear the login chime but the screen would be completely blank (black).

I tried switching between all possible Parallels modes and the only one that works is Coherence. As long as I stay in Coherence, everything works fine. But any other mode results in a black screen.

I have tried reverting to an older snapshop but that did not make a difference

 

For anyone with the same problem, this was resolved by following the directions below from Parallels tech support.

Note however, that upon first reboot (Step 4) the OS will ask you to re-install the drivers. When I did this, the screen immediately went black again and I thought it didn't work. But later on a tech support person did a remote login (LogMeIn) and as soon as he booted the VM it was working. So it seems that at least one more reboot may be required after reinstalling the graphics drivers.