Version 17.1.1 fails after splash screen (Win10)

I have just downloaded and installed the latest Studio version for Windows as released today. Trying to run the software, the splash screen opens up, closes down as usual and then NOTHING. Have tried deleting all Blackmagic files and registry entries from the PC and installing either version 17.1 or 17.1.1 but to no avail. Cannot now edit anything. Completely stumped.

Give the FAQ a good read. It goes over some things for you to do.

viewtopic.php?f=21&t=90190

For the record, 17.1.1 seems to be working OK on my workstations. Just finished a TV commercial heavy with effects, without problem.
Sorry I can't throw any light on the OPs problem though.