Sometime late last year I noticed that my internet would periodically drop out for ten to thirty seconds, then come back up. This happens for all connected internet devices. This would happen once or twice an hour. For reference, I'm running a cable modem through a NETGEAR Nighthawk router. My house doesn't have cable TV or dish, so our primary source of entertainment is through the internet. We have several devices connected at any given moment (two phones, a tablet, an XBOX, a PS4, Chromecasts, and maybe a Chromebook). At the time I was running MBAM for security on my desktop PC and it caught nothing. I even ran Super AntiSpyware and BitDefender and they came back clean. I had my ISP visit my house multiple times to check my modem, signal and cabling and they couldn't find any problems. When the signal would drop, the modem wouldn't change, but the Nighthawk would "orange-out" and come back online. Suspecting it to be my router, I ran the PC directly through the modem and the problem persisted. After weeks with tech support from my ISP, I suspected it may be my machine. So I powered off my PC for a solid week and noticed no issues with other connected devices (XBOX, tablets, etc.). When I booted up my PC, the signal drop issues happened again across all connected devices. I would also notice that the longer my PC was turned on, my mouse would begin to seriously lag and stutter when performing tasks requiring internet access (refreshing a browser page, etc.).
Last weekend I bought a Windows 7 installation disc to do a clean install of Windows. I put all of my important files (mainly the User folder that has all of my docs, music, etc.) on a separate internal hard drive, and I reinstalled Windows 7. I loaded MBAM and Webroot SecureAnywhere on the machine. I noticed that Windows kept much of my old installation and files in a folder labeled Windows.old. This made me nervous, so I ran a scan from Webroot and it found something called Win32.UserAdded in 2 spots. I cleaned the files and ran another scan. It came back clean. A few hours later, my signal dropped again.
I rebooted into safe mode and ran both a Webroot and MBAM scan. I made sure to have both programs scan the main disk and the ancillary internal back up hard drive, and to also scan for rootkits. More than two hours later, the scans came back clean. My PC was connected to the internet during the safe mode and no dropping issues occurred. I turned my machine off and went to bed.
This morning I powered on my machine and within an hour, two internet drops occurred. Is this an infection? If so, I suspect something in my old files may be infected. If that's the case, how can I retrieve the important pics and such without reinfecting a new install?
Thanks in advance.