Hello! Help me,please! I scan the computer for viruses and Avast find the following:
Sing of “Win32:Adan-156(Adw) has been found in “C:\ System Volume Information and Sing of “Win32:CIH-Monaa.
What is it? And what me do with it??? :
Disable system restore and reboot. This will remove all (and any infected) _restore points, then scan your system again and if clean enable system restore.
The (Adw) suffix relates to Adware.
Where was the Win32:CIH-Monaa file located, same place?
the Win32:CIH-Monaa is in the System Volume Information,too!
Can i just delete this fails? Can they harm the system?
What mean Adware?
Stuff in the System Volume Information folders is basically a back-up when you delete something from the windows system folders whilst system restore is enabled. That is why many anti-virus removal instructions suggest you disable system restore before removing them. So no it won’t harm the system.
Adware basically pulls in adverts, pop-ups, redirects to ad sponsored sites, etc.
thanks a lot!!! 
No problem, welcome to the forums.