micro sd chip not formatting

i have a 2gb micro sd chip and there is some files on it and lots of virus and trojans.when i formatting the chip it not format.then i scan the chip and virus is detected and removed but not formatting.when i try to format the chip by command prompt it shows it was format but when i removw chip from pc and again attach it shows its all files and not formatted.i try different things to format it but its not formatting.chip is usable in mobile.IN pc i cant able to do anything cant cut,cant delete,cant format,cant copy anything to chip.I try it by both card reader and mobile phone TO ATTCH TO PC.also try on different pc but cant.
so,if anyone can help then pls.my email is 'gaurav26500@gmail.com' you can also post mails.