Thanks, I’ll look into these further suggestions when I’m able.
But for now, yes a full PC power off and reboot has been done. I turned off fast boot a long time ago, it was there from new. Also, setting the BIOS to factory defaults has been tried without success.
I’ve checked the power lead along it’s full length by manipulating it, no break in power seen.
The lead to the motherboard is integral to the monitor. I’ve re-seated it a number of times in its socket to clean the pins. Moving it around indicates that there’s no dry solder joints there. Again, it seems intact along its length.
The monitor was reset to factory defaults as part of my initial fault finding attempts.
There is no separate video card, as I wrote earlier it’s integral with the main board.
The hard drive is solid state, it came with its own integrity checking software and using it proves it’s OK.
I’ve come to the conclusion that trying a different monitor is the best way forward. I’ll try to borrow one.
In the meantime, my wife is still using the computer, making up a stack of invoices for her business (pre Christmas rush of orders) so I’m unable to get anywhere near it; we’re ignoring the annoying monitor glitches.
Regards all!