So I have an old Acer TravelMate 6231 laptop here, running on XP SP3, whose screen doesn't work (probably inverter board problem). I'm using it only for dumb annoying Windows stuff, connecting it to an external monitor (ViewSonic VA702).
Everything was working fine and life was good -- until some crappy piece of software required me to install the .NET Framework 3.5 SP1. (when will we ever be able to do without Microsoft and its senseless array of shitty software?!)
Spent hours and hours downloading it, eventually it finished installing. So I rebooted and - WTH?! The external monitor suddenly displays a "cable not connected" error message after the Windows boot screen.
So I reboot in VGA mode or safe mode, and in safe mode I can use the monitor in 800x600 config. But that's the maximum -- I just can't go beyond a 800x600 resolution.
Tried re-installing the ATI chipset driver which is recommended for this config, but no luck -- it seems Windows automatically sets the display to a mode not supported by my external monitor. The Hardware Update Wizard finds no driver update online.
I'm considering uninstalling the driver, but doing so may not help me fix the problem (since I NEED the external monitor to see what's happening!)