I hope someone that knows what their talking about jumps in here.
First off that you had the card working seems to indicate this is not a hardware problem. If it was a simple matter of not having the proper connection settings for loading on boot up then your system would stall for a while when setting up the network, then continue to the point where you could log in normally.
I really don't know what to tell you other than read the wireless how to
. Boot into TUI mode, if you can. Make sure you have all of the correct settings in the correct files listed in the How To. You will be using command line tools which if nothing else will be an education for you.
If you get it running and all of the settings are correct but you still can't log in to the system from the GUI log in screen, then the card is not being recognized properly on boot. Someone else may be able to tell you to blacklist a driver or something.
If your card is currently set up with a Linux driver you could also tryrunning it with the windows driver using ndiswrapper. But don't expect this to work. It's just a suggestion.
I can appreciate the expression on butters face.