Well, from my understanding about computers... They don't just do things by themselves, lol. It's always user error unless the hardware is shot, lol. The title made me laugh - "Uninstalled itself."
As far as your issue, you might try using some kind of driver cleaner to completely get rid of your old driver and try reinstalling it. What kind of error are you getting when you say you can't reinstall it. It doesn't say anything? It doesn't say, "Fail, lulz" or anything?
More info, please.