Proxy Server setting keeps resetting to on

I'm trying to help a friend with a completely frustrating problem. The laptop is running Windows 7 with IE10. The issue is that any attempt to go on the internet fails with a "Proxy Server Not Responding" message. The Proxy Server setting in IE keeps getting reset to on. I untick it and then able to go onto the internet, but sometimes it will reset moments later. It always resets after a reboot.
I've followed some guidance from the Microsoft Forum and elsewhere and have so far performed:
1. Untick IE setting through Tools, Connections, Advanced etc.... ok until closing IE, when restarted it's back on.
2. Regedit and changed the Proxy setting value to 0 ( also tried 1) in the Current User, Programs, Microsoft, Windows, Internet Settings, yada yada yada.
3. Run several antimalware programs - nothing found.
4. Run TDSS and RKILL.
5. Disabled absolutely everything possible in the startup.
6. Uninstalled programs that were more recently installed.
7. And now, since my friend swears that this issue only started after she got some Windows Updates, I've uninstalled latest updates.
8. Uninstalled Avast. Replaced with AVG.
9. Performed system restore choosing a date (or event) well prior to the problem occuring.

Are there any other possible solutions? I would be most grateful for any guidance. I'm at wits end!!!!!
Thanx,
Carlo

 

Seems I've found the culprit. It was a program called Homepage from The Advertising Network. I've tried to Google it without any luck. But once I uninstalled it everything was back to normal.

Thanx for any attention,
Carlo