There was a strange file in task Manager

Daniel Suvorov
Process Conhost.exe -
this is the solution to the fundamental problems of the handling of console Windows in
previous versions of Windows, it worked with the bugs in Vista, and in Windows
XP it did not exist.

It is perfectly safe if up and running from the folder C:\Windows\system32\conhost.exe. But scanning the computer for viruses never hurts. If it is in another place, then this is most likely a virus or malware.

Windows 7 improved so that
visual Windows console handles the operating system itself. In
previous versions of Windows console process running
process csrss.exe (Client Server Runtime Process). He starts from a system-privileged account.

If you look at the command window
in Windows XP, you will notice that it always has a classic look,
regardless of what Windows theme you are using on your
computer. Due to the fact that the console window forms a conductor
windows explorer.exe and the above mentioned service csrss.exe.
PS If the file eats a lot of memory and seems useful, and if it is there
in the \Documents and Settings\ user \Application Data\Microsoft\conhost.exe
and the size is about 165k, it is probably a BackDoor infection.