Major info breech

[Stephanie Mellor]

Hi please can you tell me how to stop someone from changing their standard
log in on my windows 8 and make big changes to my computer even though I'm
the only administration of the computer?

Basically my bf has changed all my setting and he has special privileges to
all my files and from what I can c he has put a lot of my info/files on to
a USB.

He can probably read what I'm writing in this email.

Please can you help

Many thanks

Stephanie