Hey folks. I'm banging my head against the desk over this one, and if you can solve it, I will tattoo your name on my arm.
Before I start - understand that this is a personally owned computer, I'm on the admin account, and believe I have the admin token. UAC is disabled. System restore is useless, because no restore point exists prior to the date this issue started.
I have a laptop running Windows Vista Home Premium, SP2. Three days ago, it suddenly was unable to connect to any of the four types of Internet Access I have available (Wireless Router, 3g/4g network, Direct DSL, and a 'anytime' wireless USB stick).
I've updated drivers, and done everything software-wise I can think of. So let's assume that is not the issue. The network center detects each connection and can pick it up with "limited" connectivity, yet no web browser or online service can connect.
After fiddling around, I discovered that many vista services were failing to launch. Among these were 'DHCP Client', and the 'Diagnostic Policy Service' (along with anything that counts this as a dependency' .
When attempting to restart these services, I get "Error 5: Access is denied."
So I started editing permissions on all registry keys that should have anything to do with my problem. They include: