Can't delete files.... constant permission popups!

I posted this on several Vista groups in desperation. I can't get control of my own computer although I'm the only user. I can't understand the complicated directions given to OWN my own PC so I can delete unwanted files downloaded to it in error from a backup external drive.

I'm the admin and only user on my Vista comp and can't delete old files I no
longer want. How do I delete these unwanted files and why don't I have
complete control over my own PC? How do I disable all these unwanted
"safety" features in control of my PC? I have no password and there is one account - mine.

How do I get rid of the annoying popup windows asking for permission to do almost everything? It's becoming torture using this Vista machine but I'm stuck with Vista until the warranty runs out.

PLEASE!!!!!!!!! How the hell do I get control away from Windows/MS and OWN my own machine?