Windows Vista: Accidental Driver Uninstall on USB to DVI converter - Can't Reinstall

[boldspud]

So, when I initially popped in one of my two Monoprice USB to DVI converters onto my older laptop, I accidentally hit the "search for drivers online" option. This downloaded a driver that was several years old, and - for obvious reasons - did not work. I decided that the best option would be to go into Device Manager and delete the driver from the system to see if I could install the proper software I had downloaded fresh.

For some reason, though, I cannot reinstall the new driver onto this device at all. I've tried saying that I "have the disk" and navigated to the DisplayLink Core Software folder for the various .inf files, but Vista tells me they aren't compatible and that they need to be digitally signed, anyway. Nothing seems to work.

For the record, my second converter - which I connected after this whole fiasco - works just fine. It's using the correct driver from the 5.6.31870 package I downloaded. This other one seems effectively useless now, though. Please help!