Home Network Sharing Not Working

Hello. I am pulling my hair out because my son's computer will not let my connect via home network, we both are on Windows 7 Home Premium. Both computers are wired to the same router. I have tried everything to remedy the problem. First off, my son has tons and tons of games installed, I ran a virus scan and got rid of a some already. Currently, I have Cinema 4D installed on both computer and is trying to run his computer as a render client. The system runs by Bonjour service via port 5300, it acknowledges each other through the program but Windows is blocking it when attempting to connect. We also have a laptop, works perfectly through the home network and C4D. I think it is his Network and Sharing components that are screwed up. Currently, here are all the things that are wrong with his computer-

1- Error 1075
2- Error 1068
3- His Firewall is locked out, can't make changes, can't turn off or on.
4- Homegroup does not work

His computer is connected to the home network and shows connection on TCP/IPV4. Strangely, he can connect to my computer and access my shared files, but I can't get into his. I have tried everything listed on these forums, ran all those scans. Is there another way I can try to get connection? Both computers are showing each other on the " Network " tab. Perhaps using some other channels? We know that both computers are " connected ", but one is just locked out from sharing. I also have the original disk, is there a way to " blow out / delete " all network settings and reinstall the defaults only? ( keeping all his games and files ).

Any suggestions would be greatly appreciated.

Are both pcs in the same workgroup
both in the same ip range ie both have an ip 192.168. etc?
are both wired if one is wireless most routers by default have user isolation turned on this stops any wireless station connecting to the local network so if someone hack your wireless they can get internet but no personal files

Alexpho said:

Strangely, he can connect to my computer and access my shared files, but I can't get into his.

Can you please be more specific here as to what popup error message or other symptom you're seeing that clarifies what "I can't get into his" means?

Can you see the drives and folders on his machine? Or just the drives, but when you Explore downward you see no folders? Or "access denied"? Or what?

Are his drives set for "sharing" and with Permissions showing "full access"?

As was asked, are both of your machines in the same WORKGROUP (not homegroup)?

Please describe the actual error message you get, or post a screenshot.