Sharing files over my network, help appreciated

[manasecret]

There is always a user, but the password is often blank so you may not think about it.

Go to the Start Menu -> type in "User Accounts" in the search bar, hit enter -- what does your user say? (Often your name.)

EDIT:

Or more generally, since you are probably not using English, hit Start Menu keyboard key + R to get to Run -> type in netplwiz -> OK -> What is your user listed here?