File sharing working one way only... help!

[MAcsSNAcs]

I've read a couple of other threads on this, but none match my problem exactly..

I have a laptop (XP Home) and a desktop (XP Pro), and have them both connected to a router. Both can access the internet, and I have Synergy running and can access both with mouse and keyboard. The desktop can see both computers in the mshome workgroup, and can access all files and folders that are shared, but the laptop can't access the desktop. when I click "View workgroup computers" in My Network Places, I get an error saying "Mshome is not accessigle. You might not have permission...etc". Same message when I try to double click on a folder that's on the desktop. I've run the Network setup (many times) and it's set up as it should be.

The only thing that I can think of that may have changed something is that yesterday (since the power was off at my house), I took the laptop to the local library, where they have free wifi, and worked from there for the day... everything was working as it should be before I left, but since I came home it's not working properly anymore.

Firewalls aren't an issue, and neither is the router/cable/modem...

Please let me know if anyone can help me.
Thanks.

[MAcsSNAcs]

I dug around in my firewall settings and discovered that file-sharing had been turned off automatically by my firewall due to the fact that I was on a public network and my firewall thought it best to change that setting (albeit without telling me...). I guess in hindsight that's a nice feature of my firewall (Sygate, by the way), so in future I'll remember to change that back when I'm home again.