No internet

corrupted reg key maybe.
Quite often in cases like this I will just use a
small drive and do a fresh load of windows
and see if the same problem occurs

Thanks for your help. Could a test with Ubuntu be worth a trial?

I think malware is still a good bet. Spybot and Malwarebytes just can't deal with most rootkits. I sorta like Microsoft Security Essentials, but my perception is that it is beginning to slip off the curve.

Personally, what I would do is download and run Kasperky's TDSSKiller, and if it finds any infections, remove them, reboot and run it again.

Secondly, I would download and run Combofix. Read the guide before you run it. Afterward, re-scan with MBAM and Spybot. Despite the disclaimers, Combofix is generally safe to use, but you should re-run Spybot's immunization feature after Combofix, because it will probably delete your Hosts file.

Ubuntu is certainly worth a look, but I'd run it from a LiveCD to experiment with, rather than actually installing it, for a test drive. I believe Ubuntu is the most polished desktop Linux distribution around, but don't expect it to be as easy to set up and get working with your hardware as Windows.

Thanks for the info, will do tomorrow...

No malware detected. It does not matter whch adapter I use, the onboard or the additional Realtek, both give the same problems.

I recall having a silly issue long ago with connectivity and the solution was manually uninstalling all networking protocols and then manually uninstalling the device through device manager and rebooting before the system could detect the device again. Then once you reboot do not let it install the devices automatically and do an install of them by adding a new device and manually selecting the .dll files from new install files/folders that you download from another machine.

Stupid? Yes. Too much work? Most likely. Will it work? It's always worked for me.

Always worth a try!

So, did you try test running ubuntu via live cd/live usb and see if you have a working network connection? What happened with that?

Tried it (using it now) and works without a problem. So it is a Windows 7 problem.

What I do not understand is that if I look in my router my PC has IP-address 10.0.0.191, but if I look at the details of the connection my adapter has IP-address 10.0.0.199

Shouldn't that be the same?

Statically set the DNS on the network card.You can log into your router and get the DNS srvers assigned by your iSP and then hardcode them in the network card.
Windows 7 and vista sometimes have issues with DNS and routers. They both query Microsoft every so often and if they cannot resolve the domain name they show a limited connection.

Changed it, but still no connection.

What make and model router? Have you checked that it is in fact windows 7 compatible?
Some routers are not compatible without a firmware update

It's an Alcatel Speedtouch 510 from 2003.....

Back up your data, and do a format and reload.