A bit of googling seems to show that I should trash my settings file but I'm afraid i'll lose all my custom settings.
If this is the case, there likely isn't much that anyone can do for you. If it turns out that one of your custom settings is triggering some odd quirk in Photoshop's rendering engine, well, that setting has to go if you want your cursor back - and there's no way that people across the internet can trouble-shoot that problem for you.
Honestly, trashing the prefs isn't so bad. It's not unheard-of for people to uninstall/reinstall the entire Creative Suite when Photoshop misbehaves. If you can get out of the jam for the small price of default preferences, you're fortunate.
You may also want to peruse the answers on another Photoshop-bug-related question: Can't see the canvas (it's transparent)
At the end of the day, this sounds like a pure hardware or configuration bug - file a bug report if you feel so inclined.