If you are having trouble logging in, there are a couple things to check first:
1) Make sure the Num Lock is set correctly.
2) Make sure your CAPS LOCK is not on and you are entering everything as case-sensitive.
2) If you recently changed your password, make sure you are using your NEW password - not the old one!
If the problem continues:
1) You can ask any staff member for assistance (if you are on campus).