Can't access shared folder on network.

I can't access a computer on a network. I see the computer listed in "My Network Places", but all I get is a prompt for a password. I have tried entering the administrative password, but still no access. There are 2 shared folders. I have tried it from multiple computers (with and without administrative privileges). All computers are Windows XP. (The computer I am trying to access is SP1, all others are SP2).

How do I enable access to the computer?

disable the guesst acount on the computer...