No internet

[panhead]

My onboard Intel 82566DM-2 now and then refused to make internet connection. The last few days it almost stopped al all. Sometimes after 10 restarts it worked again. So I installed a Realtek 8169 network adapter which worked the first time and then gave the same problem: no internet connection.
All other computers/laptops in the network have no connection problems at all. I switched cabled to no avail.
Anyone a suggestion where to look for a solution?

[Niclo Iste]

Have you tried a different port on your router/switch?

[Guts3d]

Checked for viruses or malware? Swapped cat-5 cables? Ensured that the cable is plugged in tightly?

[panhead]

Yes. I switched ports and cables, connected directly to router.

If I start computer I get no connection, if I then switch cable from the onboard networkadapter to the Realtek network card I do get a connection (and vice versa!). So the one I start with does not work and switching makes it work....

[Guts3d]

Assuming you have XP, when you have no connection, try hitting the Start button, choose Run, then in the resulting box type CMD and a DOS box will appear. Tyoe "IPCONFIG /FLUSHDNS", then hit enter. Then type "IPCONFIG /RELEASE" , hit enter, then type "IPCONFIG /RENEW" all without the quotation marks. This should flush the Dynamic Naming system of old crap, release and renew your IP addy. It doesn't matter if you use all caps or lower case letters.

[panhead]

Thank you, I will do next time (I use Windows 7, but that makes no difference.)

[panhead]

Guts3d,

Your solution works, thank you. Do I have to do this every time I logon (I tried it several times and had to do it each time)?
Was is the cause of this behaviour?

[Ferrit]

Unlikely, it sounds like you are infected.
Once should be enough.
What antivirus do you have?
What malware cleaner have you used?

[panhead]

I use Microsoft Security Essentials and Spybot Search & Destroy.
Both found no viruses / malware.
Try another one?

[Ferrit]

You can certainly try Malwarebytes
Install it update it and be sure you do a full scan.

[panhead]

Full scan done, no problems

[Guts3d]

Suggestion; go to control panel and create a new account ( limited, of course! ) and see if that has any problems hitting the net. If not, it might just be a corrupt account. If it has problems, you might want to boot into safe mode and scan for viruses.

[panhead]

Another account, same problem.

[Ferrit]

Pretty much whats left is a format and reinstall.

[panhead]

Well, that is of course an option. What could be the cause of this behavior?