There were two more methods not listed that you can try. 1/ In Control Panel/Device Manager, disable then enable the relevant network card. You didn't say whether this was wired or wireless. If you used the W7 Troubleshooting function that might already have been done. In which case, what did it report?
2/ In the W7 Command Prompt, type: IPCONFIG /RELEASE followed by IPCONFIG /RENEW