Firefox and Proxy settings! :mad:

hi,
i am currently on a university network that uses a internet cache. as such i had to enter the proxy address into the connection settings in both IE and FF to use the internet. now all was running fine until today. all i did was download a program to hide your IP, which didn't work anyway. so i uninstalled it and when back to things as normal. but now for some reason every time i close FF is looses the proxy settings. so now i have to enter them every time i open FF, which as you can imagine is a pain. any one know how to keep them their permanently again.