3 Vista Computers, 1 with error message 0x80070005

Hello,
I am trying to network 3 computers all running Vista.
Computer 1 can access the shared files on computer 2 and 3.
Computer 2 can access the shared files on computers 1 and 3.
Computer 3 can access on computer 2 but not 1.

Computer 3 when it opens up computer 1 it can see the shared items (with the
pipeline), but when you double click it denies access as folllows:

Windoes cannot access\\computer1\c
Check the spelling of the name. Otherwise there might be a problem with your
network. To try to identify and resolve network problems, click Diagnose.

Click See details>
error code 0x80070005
Access is denied.

Click Diagnose>
c was available but the user account you are logged on with was denied
access.

I have permissions set up on computer 1 correctly because computer 2 can
access shared files on computer1.

I am running all computers as administrator.

Any solutions,
TIA
Don