Windows 7 - Windows Cannot Join Homegroup on This Computer

I have 2 new Acer computers, both running Windows 7 Home Premium. I am attempting to share files on a homegroup for the first time.

I can create a home group on either computer, but I get this message when try to join the newly created home group from other computer: "Windows can’t join homegroup on this computer " In other words, both can create a homegroup, but whatever the one creates , the other cannot join.
One important note is that one of the computers does not have the three network adapters the other has. It is missing a wifi adapter although it has a wifi port. Could this be part of the problem?
Following are the 18 steps I have completed to date, all of which were redone by a "for fee" networking service except for resetting the router (I had already done this multiple times). These are not necessarily in the order I did them and I retried creating and joining a homegroup on both computers between each "fix." I checked the status and network map on both computers between steps to verify changes were registered correctly by both. Various corrections were made along the way, but none worked.
(Note: I do not want to individually share files or folders. Due to my specific needs, I want to get the homegroup working.)
1. Checked for same workgroup, homegroup, computer name, user name and password on both computers, both computers have security setting set to home. Renamed each one of these individually and then returned to original name. Rebooted between each step. Checked that both had same network map.

2. Ran trouble shooter until no problems found on both machines. Rebooted
3. Reset both clocks to internet. Rebooted both
4. Unchecked needing a password. Rebooted both
5. Turned off firewalls on both computers. (Risky I know, but running out things to try).
6. Switched which computer was creating and which was joining. Rebooting between .
7. Left the homegroup on both computers. Rebooted both. Created new homegroup on one computer and joined on other. Rebooted both. Repeated process with creating homegroup on opposite computer. No success.
8. Made sure both computers had same advanced sharing settings including turning on network discovery and turning off password protected sharing. Rebooted.
9. Both PCs left homegroup. Rebooted both. Reset both computers to public security settings. Rebooted both. Then set both back to home. Rebooted. Set up homegroup on and then tried to join on mine. Didn’t work. Reversed.
10. Reset router and created new network and began again with everything multiple times
11. Disabled all other network adapters on both computers.
Created ethernet connection both computers with ethernet cable and tried again. no success. Rebooted both.
12. Unchecked and rechecked IPv6 box back on in connection settings. Rebooted
13. Checked that Peer Networking Grouping and Home Group Provider services were in “started” status on both computers. They were but I restarted both.

14. Navigated to the idstore.sst in the following location C:\windows\serviceProfiles\LocalService\AppData\Roaming\PeerNetworking, deleted it, restarted both computers. No success.
On Both Computers:
15. Ran windows update
16. Ran antivirus and malware
17. Ran utilities cleaning up registry errors and registry defrag multiple times during process
18. Ran chkdisc
Have spent 3 days on this, including calling a networking fee service associated with cisco (I have an E3000 linksys router and both computers have 802.11b/g/n). The fee service concluded the problem was a microsoft bug and gave up and told me to call microsoft...but apparently they will only help if I bought the windows 7 home premium separately from the computer. Thank you for reading all this. I would be soooo very appreciative of any help.

Hi sanjarver, I had the same problem as you, I read everything I could and still it would not work. I had made a system back up image with Acronis 2010, so was safe to experiment till the moon turned blue. First thing I did was remove ALL my AV/AM programs and Outpost Firewall Pro (desktop) + Outpost Security Suite free (laptop) set advanced adapter (network) to default/recommended settings, installed MSE v2 on both pc's. Set Homegroup on desktop, joined it on Laptop and it worked perfectly.
Previous attempts with firewall's disabled and set to 'auto learning mode' failed.

Thank you! Thank you! Sorry for the delay in responding, but the backup image was a little above my head and threw me, so it took a while to implement. I too had disabled firewalls and antivirus which didn't work. But adding your suggestion of removal of the firewall/antivirus programs to the following 9 steps did work. Don't know if all were necessary,
1. Uninstall firewall/antivirus programs on both computers: Blink on one PC and McAfee on other
2. Disable wireless adapters on both computers and connect them via ethernet
3. Leave the homegroup on the "joined" computer
4. Reset the router and create new network
5. Create homegroup on one PC and join with other.
6. Disconnect Ethernet, Enable wireless network adapter.
7. Joined wireless network (creating wireless configuration) on each computer. Windows then shows 2 networks with same name (except one name has a number after it).
8. Merged the two networks
9. Tested to see that homegroup still functions. Success!
For other people looking for a solution, I also found the following link on this site and implemented any unimplemented steps there before beginning steps 1-9. Ultimate Troubleshooting Guide for Windows 7 HomeGroup Connection Issues

Hi Sanjarver, congratulations. I had been on the site in your link plus a few others. At this moment, I'm not using homegroup, partly by choice and pure luck. I am using the 'Network' connection, and can access Laptop to Desktop only, not that I'd need it in other direction, as my Laptop is only on if I'm using it. I know you'd love to know how its set, so will tell you later if you ask.