Windows 7: Able to see other computers in my homegroup, but cannot

I have three home comupters in a network. One is a desktop plugged via Ethernet cable directly into my motorala router. The other two are laptops connected wirelessly. All computers are in my homegroup. One of my laptops can connect to and transfer files with the desktop. The other can "see" the computers in my homegroup but I cannot connect to it or connect from it to either one. I have tried disabling all firewalls to no avail. The computer that can connect does so with Norton's endpoint protection firewall enabled with no issues. Can anyone offer some help, I'm at my wit's end here.

Are all of your machines Windows 7? They need to be if you are using Homegroups.
Try going down this Homegroup check list to make sure everything is set up correctly. Pay particular attention to the time/date settings and the registry adjustment part.
Ultimate Troubleshooting Guide for Windows 7 HomeGroup Connection Issues

If that that check list doesn't help than most likely something is blocking the connection like an A/V software or a third party firewall.

Yep, all machines are windows 7. I've tried using both safe more and turning off all firewalls with no luck. I've also run through the homegroup troubleshoot guide.

Often times disabling the firewalls or disabling the A/V won't fix the problem, sometimes the only way is to uninstall them completely, it'a pain but often times it's the only way. Norton can cause problems just like this also.

I'm hesitant to uninstall Norton when it seems to work fine on 2/3 machines. I'll give it a shot though.

Complete uninstall of Symantec had no effect.

I had a similar problem with endpoint. It was on a fully functional machine on my lan and this machine had no problems. However when removed the machine with the problems (no endpoint on this) was cured! just some food for thought.....