I have two computers, both running Win 7 Pro. One performs normally in all ways. The other was fine until a few days ago; we moved from a hotel WiFi network to a residential cable modem/router, and anything requiring an internet connection suddenly became very unreliable. Browsers spin their wheels endlessly, Outlook 2010 won't connect to the Gmail IMAP servers, and so on. The network connection is fast and stable from the other computer. Both computers run Avast Internet Security, with weekly full scans scheduled. Both the hotel and the residential networks have been treated as public networks. A quick scan with Avast revealed no malware on the malfunctioning computer. The good computer is an old HP Pavillion DV7 4070us, the bad one is a newer Sony Vaio VPCSC1AFM. Nothing else has been changed recently.
I tried Malwarebytes. Initially, it balked at the update, but after a restart it updated its database successfully. It froze when I tried a scan. I ran Rkill (nothing detected) and TDSSKiller (no threats found) then Malwarebytes again (no malware found.)
I also have tried changing DNS servers, and disabling IPv6.
I have tried the malfunctioning computer on a guest network at work, and have experienced no difficulties there. That points to something on the residental network that isn't getting along with something on the malfunctioning computer. I'm not knowledgable enough about how networks work to identify what the difference is between the good computer and the bad computer that is causing it to misbehave at home.
Any suggestions would be most welcome.
Edited by bcgirton, 27 March 2014 - 12:18 PM.