Whenever I tried setting up the Windows 7 HomeGroup, I kept getting an error message about the password not being correct though it was correctly typed in. COMODO Internet Security was blocking it so this is how I fixed it...
1) Open CIS.
2) Click on FIREWALL at the top.
3) Click on MY PORT SETS.
4) Click ADD > A NEW PORT SET. Call it HomeGroup. Click APPLY.
5) Now find HomeGroup on the list and underneath it, it will say (add ports here). Click on that then click on ADD > A NEW PORT.
6) CIS seems to use both TCP/UDP at the same time so there is no selection for this in CIS. Dot the circle in front of ADD A SINGLE PORT and add port 3587. Click APPLY.
7) Repeat the above and add port 3540.
8) Now go through the HomeGroup setup wizard and everything should work.
In case you use these directions for a different software firewall program, 3587 is TCP and 3540 is UDP.
Also be sure your Network is set to HOME in Network and Sharing Center.