My pc is infected by any worm etc which changes the names of drives and when i try to open by double click and open with dialog box opens.
e.g. the name of my C dribe become “/``~~!>” etc.
Have you run scans with avast or other security programs such as Spybot-S&D, Spyware Terminator, etc?
Yes but it remain there
General info on changing drive letters may enable you to change them back, http://www.dougknox.com/tips/xp_drive_letters.htm.
My friend google may be able to throw some light on it, http://www.google.com/search?num=50&q=drive+letters+changed+virus. See if there is anything in the results that match your problem.