-(minus) sign before an attribute it means removing attributes and +(plus) sign mean giving attributes to the file or folder.
example ) attrib -r -a -s -h file.txt this will remove all attributes from file.txt and attrib +r +a +s +h file.txt will give all attributes to file.txt .
If pen drive or other hard drive is infected by virus ,Command prompt is the best option.Follow the steps given below.


1). Go to the command prompt by start>all programs>accessories>command prompt or press windows key+r and enter cmd .


2). Go to the drive where you want to delete virus example write d: to go to D drive .


3). Type “attrib -r -s -h *.* /s /d” without quotations and press enter .


4)press dir /a .


5). Delete all the .inf, .exe , .dll, .log extension file if they are not your files by using dos del command .


Example:

del autorun.inf

if any file is not deleting rename that file by rename command
Example: rename dst.exe ms.bak this will rename dst.exe to ms.bak



Now Your pen drive is virus free .