First of all, thanks for the replies guys.
Saltgrass - I've tried it without drivers (that is, generic PnP), then I've installed drivers for the one not working, and, when that didn't help, I updated the other one as well. It upped my refresh rate, but not much more. Yes, both are DVI, and both drivers are digital, and have the proper driver name (L1750HQ(Digital) is how it shows). Yes, both monitors needed updating manually and separately.
Also, what you're describing, where one screen boots and the other shows Win 7 is exactly what's happening to me.
TorrentG - Yep, I've fooled around hoping anything would get a rise out of the dead monitor, to no avail, and I've also returned it to the settings you've mentioned.
zvit - confirmed latest drivers. As for UltraMon, I've tried it now and while it has some neat features, unfortunately it behaves the same way Windows 7 does - as if the monitor is plugged in, working, and everything is peachy. Trying to change the settings doesn't do much either. How upsetting.
Interestingly enough, if I switch between primary and secondary the same screen that's working becomes the secondary while the primary is still dead. So it's nothing to do with which is what, and more to do with one output working and the other one isn't. Huh.
Thanks again for the reply, btw
Help!!