I'm using window 8 and I found "mrt.exe._p" file and "mrstub.exe" file other than the drive in which window is installed and it disppear after few minutes. Is it harmful or not?
Thankyou
The files "mrt.exe._p" and mrtstub.exe (72KB) are related to Malicious Software Removal Tool. You can download it from here
It probably isn't a virus, but to be safe search for the files on your computer look into Hidden Folders & Files, right-click go to properties and see if it has the Microsoft Signatures. The most likely reason of it disappearing is because after every scheduled scanning by Malicious Software Removal Tool, the files are suppose to be deleted.
You should also check your logs to determine the last scan performed by MRT.
Ctrl + R (open Run dialog) type: %systemroot%\debug
you probably have a file named, MRT.log. Open it in notepad then check the last time it performed a scan.
If you find that it didn't scan your computer during the period that you found the files, then it could be a virus/malware.
I advice you to install a free anti-virus program, since you don't have an extensive knowledge of how to determine if a file/pc is infected.