Windows External Display Q - Long Shot

[2Btoo]

Hi,

I'm having problems with an external display connected to a Windows machine at church. The question is very vague and I don't even have that many details but I'd appreciate any suggestions that anyone may have. Details are thus;

- Machine is a Compaq laptop, running (I think) Windows 10
- It's connected to a Kramer SID X2N (one of these: https://www.thomann.de/gb/kramer_sid_x2n.htm), via an SVGA cable. The Kramer device acts as an input switch to feed HDBaseT out to a large Christie projector. This presents itself to the laptop as the projector itself - i.e. the Kramer device is transparent
- The machine is used once a week and has worked fine for a year or so. However the last time it was plugged in and used it didn't behave as it should have done. No matter what the 'Display' settings on the laptop were set to the laptop screen blacked out whenever the SVGA cable was plugged in. If you unplugged the cable and told the laptop to mirror or extend the screens the built-in one blacked out again when the cable was plugged in
- When this happened the display on the projector worked intermittently but at a very low (wrong) resolution.
- Plugging the SVGA cable into another laptop worked fine, suggesting that the problem is with the first laptop
- Running the affected laptop off a USB Boot Stick with Linux Mint on it made it work fine, suggesting a software problem with the laptop in question
- Plugging the affected laptop into a different projector (smaller portable one) meant it worked fine

The issue therefore seems to be with the Windows installation on the laptop not wanting to work nicely with the external box/screen. The machine is used by two or three people but none of them are likely to have played with the settings on it knowingly (although may have changed something unknowingly.) Therefore there is no clue as to how this problem has arisen.

I know it's all terribly vague but has anyone seen anything like this before or able to help at all? I'm clueless with Windows these days (I stepped off the MS bandwaggon back at XP) and for preference would rebuild it as a Linux box, but this probably won't be popular.

Thanks .... if anyone is able to help!