I have been worried about having a compromised system for quite some time now - particulary after reading "scary" stories about botnets and what not. I am using Windows 7 Ultimate, with Malwarebytes Premium and Avira Free as anti-malware protection. As for the firewall, it's only been the native Windows Firewall operated via an tiny extension called Windows Firewall Control (188.8.131.52), with medium security settings, but I'm not confident enough to use this and will probably try out Comodo once my issue has (hopefully) been resolved.
My current problem started yesterday. I woke up and checked my email, everything was working fine, no anti-virus alerts, nothing. After grabbing a coffee, I noticed that my connection was down. My pc wouldn't recognize my router connected through a LAN cable. Windows troubleshooting didn't fix it. Also, the router and connection were working just fine, because I could connect to it with my mobile deviced. I strongly believe that it is some virus that now causes my system to malfunction.
I'm using a Broadcom NetXtreme network adapter to connect my pc to the Internet via cable. After checking the Device Manager, I noticed that the adapter has somehow disabled itself and checking the settings said that no drivers could be found. I looked at the driver path and everything was normal. I checked the driver path manually, it's a native Win7 driver found under "C:\Windows\System32\drivers\b57nd60a.sys" and nothing appears to have been modified within the file itself.
I run a MB malware search - nothing turned up. TDSSKiller - nothing. I tried to run Avira, first their Rootkit/active malware search, but it would freeze while trying to access hidden objects. A normal, full scan also wouldn't start - it would be stuck at the boot sector search, not having browsed any files at all. It wouldn't let me cancel it - it would freeze until I relogged.
Also, the computer wouldn't stop searching for the network, even after I: 1. turned off the router/modem, 2. disconnected the cable. I couldn't disconnect the LAN connection through the connection settings window - Explorer would freeze, too, then crash and restart. I tried to restart the Broadcom driver in Device Manager, but it would also freeze. I tried to disable the automatic "Network Discovery" - no changes to the Advanced network settings wouldn't aply and it kept on looking for an adapter.
I backed up some files and decided to just restart the pc. Unfortunately, I did not boot into safe mode... However, everything seemed to be "normal". The fixes I tried earlier have been applied - the Broadcom driver was recognized/accepted again and the device was ready to use. The network device search stopped and it just said that there's no connection. The "Turn off network discovery" setting was applied, too. Furthermore, Avira would now do scans - and find absolutely nothing. Same with TDSSKiller and Malwarebytes. The system was extremly laggy during the almost 5-hour-long Avira full scan, though. Also, in Task Manager, the CPU-usage displayed would differ from the apparent CPU use by the processes that were running, it was as if there was some unknown background process running (invisably) that hogged additional CPU power during the scan. It occured during the Avira scan and during other operations. It's as if the Task Manager doesn't display the memory used by processes correctly.
I would like to add that I have not connected my pc to the web after the driver problem occured - and while I was using my anti-malware software. I was afraid that whatever was on my pc would wreck havoc on my computer once I reconnected...
I decided to restore my connection because I'm out of ideas as to how to find the culprit and remove whatever it is that has attached itself to my system. I do hope you can guide me through a proper recovery procedure.
Thank you very much in advance for any assistance!
Edited by cladiel, 19 September 2014 - 03:28 PM.