Administor Account



I never set up a 'Administor' accound, didn't know I had too. But somehow one
was set up, using a screen name I haven't used in a year or more.
I'm now being asked for the password for every change I want to do, a
password I never knew. I'v tryed many things mentioned to get this password,
or change the sceen name & password my computer knowes.
My computer is running Vista 32-bit Home Premium, it's only 2 years old. I
can't download, or update any programs,or go into 'Control Panel' & make me
the Adminisitor.
Anyone have any more ideas?
.