I have three computers running on W7. A couple of days ago, one of these computer starting having problems with internet access.. First, I thought it was the router but connecting this computer directly to the broadband modem via Ethernet cable gives the same problem. No problem with the other two computers so I believe the broadband service and modem are fine.
So what is the problem with the one computer? The connection appears normal when viewed in "Network and Sharing Center". However, both IE10 and Chrome will only open a few sites and very slowly and inconsistent.
I suspected a DNS problem but specifying DNS servers did not help. I have power booted the system i.e. shut everything down and disconnect cable. Then reboot modem, then connect cable, then power up computer. That did not help. I tried to do a System Restore but that failed. So I restored the system from a image backup taken a few days before the deterioration of service.
I have run scans by Malwarebytes and Spywareantispyware. I have disabled Hostman.
I have done ipconfig /flushdns. I have done ipconfig /release and ipconfig /renew. I have diabled anti-virus and firewall.
I have run out of things to try so am submitting here for help.