Tried that Mistereo and nothing
I'll try clearing the DNS/DHCP caches.
What are the command for that again?
ipconfig /flushdns (will clear DNS cache)
I'm not sure the command to clear DHCP entries.
Also, I'm assuming this is a standard PC.... You should only have one network adapter listed under ipconfig /all.
If you are comfortable uploading that information here, run this command in command prompt "ipconfig /all >> C:\Users\%username%\Desktop\ipconfig.txt". That should create a text file with the ipconfig results. Copy and paste the contents of the "ipconfig.txt" file here. If it is showing more than one "Ethernet Adapter Local Area Connection" then that is likely a related issue and could be the root problem. If you can successfully remove all extra connections I would be willing to be you would be able to rejoin the domain.
Lastly, this is kind of a superfluous question as I know what the answer *should* be in a business environment, but your organization is
running a good, up to date virus protection program, right? And this program hasn't discovered any viruses on the PC?