No signal to external monitor. All drivers uninstalled and updated.

My external monitor has recently lost the signal from my laptop and I've tried every bit of advice out there to try to get it back, with no success. I have a Dell XPS 15 9550 laptop, and an old Dell S2409W external monitor. It was working fine via a DVI-D cable, but lost it's connectivity at some point when I was uninstalling / updating drivers for a Zebra LP2844 printer; as part of my troubleshooting the printer, I deleted a few drivers that were showing errors in Device Manager (stupidly without noting what I uninstalled). Once the dust cleared, the monitor no longer works.

Details of what I have tried:
Currently, there are no errors or conflicts displayed in Device Manager. It only shows a Generic PnP Monitor.

I have replaced the cable, no effect. I have tried an HDMI cable, but the monitor is locked on DVI-D input, and I cannot unlock the menu to select another input. I've tried unplugging the monitor and holding the power button down for 15+ seconds for a hard reboot. No effect.

I have uninstalled all monitor drivers, as well as NVidia, run both Dell and Intel driver updates. I have installed the specific Dell S2409 driver onto the Generic PnP driver. None of these has had any effect.

The monitor does power on, and the display works - it just shows "Entering Power Save Mode" when plugged into the laptop, then goes dark. I don't have another machine with a graphics port with which to test it unfortunately.

I've run sfc /scannow, I've run Windows Update.

I'm at the point where I'm considering a complete rebuild, but would love to avoid that if anyone has any further advice to try.

Thanks!

Thanks Ken. Unfortunately that didn't do it either. I uninstalled both Nvidia and Intel with DDU, then reinstalled both, as well as the monitor-specific driver and it's still not getting a signal.

I tried booting with Kyhi's recovery disk and there was no signal as well. The battery is enclosed, though I could unscrew the back and get to it if there's a chance that might help.