i have a Desktop computer, i forgot my password and i am adminitrator, so i only can use my pc by GUESS account and i don´t have permission to do a lot stuff...I NEED CHANGE admin PASSWORD USING THE GUESS ACCOUNT... i wait for feedback!!!

You have a problem, for sure, and if your problem is truly legit, I feel sorry for you, as it is against the rules here to help anyone to recover passwords. My tip to you, however, is that in most cases the Administrator password is blank. Don't type anything there, just enter and see what happens.

Your options are:

1. Read this short article: http://support.microsoft.com/default.aspx?scid=kb;en-us;Q321305

2. Try to do a repair install using your windows installation CD.

3. You may have to do a complete re-install.

4. Google is your friend, realy!