Why can't I read my portable hd on my windows 7 desktop from my vista laptop?

I have Windows 7 on my desktop and a portable hard drive connected. I enabled sharing on both of them. On my laptop I have vista. They are both networked on my local Linksys router. When I go on my laptop through the network it shows my desktop computer but it requires me to give a login and password. I did not pw protect the vista computer. What is going on?

2010-10-28T00:03:56Z

How do I look at the hard drive files? How do I get past the stupid login screen? I've tried everything.

a9012010-10-27T21:24:20Z

It's probably just the administrator password popup, just asking for permission to connect to a foreign device.