Windows Vista-32

I'm logged in with my admin account and trying to change some rights
on a folder and a file but it keeps telling me I need to provide
"admin permission"

Why is it doing this - I AM the admin its a single user laptop there
IS only me and I have an admin account.

It isnt even allowing me to GIVE permission or telling me how to do
so.

Can someone tell me how I can gain TOTAL control of MY files
on MY computer please?

No waffling about what is or isnt safe please - I need to control my
laptop.

I'm so annoyed.

thank you

pamela.