i tried to sign in using my user name and password but it keeps telling me that it is invalid so i would like to know if there is a way to reset them. i have used this software once and like it very much, but is there a way to reset the login information

You have to login using your eBay user id and password.
If you forgot your password, you can reset it using eBay site.

If you believe that your password is correct, please check this forum thread for possible solution:
http://www.myibay.com/forums/viewtopic/1316/short-or-weak-password-will-prevent-you-from-bidding/