CIS froze itself and OS while scanning critical areas

I have CIS 5.0.162636.1135. CIS froze my PC not only its application. I have read the topics and the FAQ, but did not find a case exactly like mine.
I ran a scan (critical areas) yesterday. I have administrator privileges and this not has been the first time I ran a scan. Everything had been okay with it till yesterday, but yesterday CIS froze. After scanning had been running for over 3.5 hours… It was suspicious. The radar animation was still working, so I thought that the scan was still running–but the same file had been checked for hours and the number of checked files did not grow. Actually, I tried to stop scan process, but failed. Tried to close CIS, but CIS was frozen too. Tried to close the application used Task Manager, but was unsuccessful. Tried to shut down my PC, but no response the OS was frozen as well… In the end Start menu-Shut down process seemed to be working, but after the shutting down blue screen (The Windows is shutting down) my wallpaper returned with no icons, and CTRL+ALT+DEL did not help to try to shut down as there was no response. I had to shut down my PC manually, via hardware (it is called hard reboot I think)–I mean I had to switch off my PC itself as the software did not response. The scanned file was somewhere in Documents and Settings folder that caused freezing.
I have XP SP3 and the OS updated. I have no other security software I have CIS only.
Is it a bug or an infection?
I am scared as this has happend to me when I used another antivirus program. When the AV froze something happened… Afterwards my AV was malfunctioning and in the end I had to reinstall my PC as it went totally crazy and out of my control.
Help me please!

Thanks so much in advance!


I have just tried to scan my PC with Comodo Cloud Scanner. I wanted to run a deep scan–54% of my PC was scanned when I received an error message by Windows saying that an error occured and Windows has to close the application.
Actually, at this point I have no chance to have my PC scanned.
I am really scared! I have reinstalled my PC only 1 month ago! Please help me! :frowning:

Try scanning without Cloud Scanning enabled in the Antivirus Scanner Settings.

There are a few of us with similar problems:

Thanks. I have just read cases you linked. I will try to do as it is suggested–and will return if I fail. It is very delightful that it doesn’t seem to be some malware.