I am using a Windows 7 laptop with McAfee installed when I suddenly got a message that something Windows Firewall blocked a part of Microsoft SharePoint Upload Center called groove.exe. I was a bit surprised (and also a bit dazed off) and made the terrible mistake of disabling the block. After a few minutes I saw that my taskmanager was greyed out and when I started task manager via the command prompt I got the error message that task manager was disabled by my system administrator. Also regedit was blocked the same way.
At that time I knew I was infected. I ran McAfee scan, CCleaner and Malwarebytes and was able to remove the virus. The task manager and registry editor were again available.
A couple of days later I suddenly saw my task manager again greyed out with the same error message. I ran Mcafee again, CCleaner and they removed stuff but not the virus (as the task manager was still greyed out). Strangely enough I saw that Malwarebytes could not be opened again. It just did not show any graphical interface.
Running Bitdefender did not help either (it ran but could not remove the virus as task manager was stil greyed out).
I then used combofix and it removed files and now my task manager is again available as well as the registry editor. However still Malwarebytes cannot be run.
I have a log file which I can share if needed. I sure want to know what I really says.