BleepingComputer.com: How to delete saved password that has already been connected / mapped to another drive / shared folder)?

How to delete saved password that has already been connected / mapped to another drive / shared folder)?

I have 2 PCs. 1 is Vista for me. 1 is XP for my relative. When my relative connect from the XP to my Vista for the 1st time, it asks for the username and password. After it's connected successfully, how do I delete the remembered password in the XP machine so that my relative can't access to Vista machine automatically? And how can I enforce the XP machine must input the username and password for every single time that's connected to my Vista?

I did not set any network password, so it's my windows login username and password. I can't change the password for the moment because I have hooked up to many other devices using the current password.

If you have any solutions, please specify whether the steps are done in XP or Vista, appreciate much.

By the way I have already tried "control userpassword2" or "rundll32.exe keymgr.dll, KRShowKeyMgr" trick and it does not work because all the user account listing are just my email passwords.