This is the trick to remove some of the Virus which comes mostly from Pendrives, when you don't have a Antivirus installed or your Antivirus is not updated.
Most of the Pendrive Viruses have an hidden "Autorun.inf" file inside them so that as soon as you double click on the drive icon the "Autorun.inf" file gets executed and the command in this file installs the Virus in your Computer.
So, Mostly the Pendrive virus is made up of two parts
1) Autorun.inf file ( mostly hidden ) [ Not all autorun.inf file can be considered as virus, as this is the file responsible to autorun any file]
2) Virus File ( mostly hidden )
So, if you don't have any Antivirus installed or your antivirus don't detect the virus after scanning then,
Insert your pendrive. Cancel the autorun menu comes as soon as you insert it.
Now, goto "My Computer"
Right click on the drive and click on search
now in the first box type "*.*" without quotes
and see to it in the Advanced option below that " look in hidden and system files" is checked so that all the hidden files are included in the search.
Let the search gets completed. Now find the "autorun.inf" file in the list and open it
now in this file will be the supporting virus filename. search for that file in the search result with the name in that autorun.inf file and delete it.
Now the viurus file is deleted. you can now delete the "autorun.inf" file too.
Now you are safe from the virus being executed on your system.
Now remove the pendrive and insert it again and you can use it safely :)