totaly removing the default share on a PC joining the Active Directory

Hi all,

If can anyone help me with this, will be great.

I am a domain administrator, running windows 2000 Adv Server, and
windows 2000 Pro and windows XP on clients side.

One of them has done something, and now i am not able to access that
server;
Start --> run:
\\computername\c$
It gives me username and password.

I put username and password of the administrator, it won't let me go
in,
it regives me the username and password box.

I tried to put DOMAIN\username and password, same problem.

I went physicaly to that PC, and logged on with administrator.

It gives access denied on any folder i want to access.

I tried to change the owner, replace..., i couldn't. It says you don't
have access to change them.

What do you think the problem is, and how can i solve this.

Thanks and appreciate it anyway.

Eddy