I've made a tiny bit of progress on this, but it's only a faster way to fix it.
If you go into Standby mode and then get out of it the screen is no longer messed up, so at least you don't have to completely restart it. I no longer think that the 5 monitors thing has anything to do with this, I've messed around with video drivers and I noticed if I used laptop drivers then the 5 monitors showed up, but if I used the device manager to install the desktop ATI Radeon HD 2600 XT then only the plug and play monitor showed up, like in TofaPrune's screenshot. I'm pretty sure the 5 monitors thing is just a laptop video card driver thing.