cannot open excel after change user name

please help.

i'm using excel 2007.
i have some excel files which protected with password.
then i thinking to change the user name, so, i just change it straight away, then, i closed the file.
but, the problem is, when i wish to reopen the files, all protected excel files, i need to change the user name before open those files. i need to do it everytime.
i know i'm lucky i still can open password protected files, but it really not conveniet and it's very weird, and also wasting time, to change user name(just to cheat pc, or that's what i feel) to access files.

please, anyone can help me?


thank you.

seemed that can't edit my question.

i solved the problem myself.
not excel problem, was my pc problem.

solution:
excel property=security, check user permission or edit.