PC slow when plugged to network

Hi,

I have a PC running on 64bit Windows 7 which was part of a domain at my work. Now, I got that PC at home, made it a part of a Workgroup instead of a Domain and it is ok.

But, when I plug the Ethernet cable, the PC becomes extremely slow. It's a Core-i5 w/ 4GB RAM.

By any chance this is due to some restrictions from the Domain management system that are still there?

Already run Avast and Malwarebytes scan, the PC is clean.

Thanks for any help.