Vista - Vista gives 'Access denied' error msg

When connecting from one Vista machine to another (laptop to server), I'm getting a 'access denied' error msg when tring to see the contents of the c:/on the server. I have permissions and sharing setup. I'm ultimately trying to get Peachtree Accounting software setup. When I try to connect databases, it won't let me connect the laptop to the server sitting in another room. On the server I've basically set all the permissions to wide open so that any computer can connect to it, yet nothing will. This is very frustrating because this is the bosses computer and he needs to get this installed ASAP. I can see the server and all the drives, but trying to access anything will get me an access denied error. There are no passwords on this network as this is a very small company. I've been looking at all the blogs and some other help sites and I haven't seen anything that helps.