in my c drive i've got something called a MS-DOS Batch File and i'm not sure whether it is a virus or not. i scanned AVG and norton onto it but nothing comes up. If i delete it it comes back when i turn my computer back on.
Did you run spyware software? Also what Windows are you using? As far as i know there's no Ms-Dos files on xp.
Unless your using some sort of software that requires dos files, that would be why it keeps coming back but that could also be a sign of a virus or spyware judging by the fact that it's only called "a" i would say ups up to no good...but if avg is not picking it up… Download CCleaner: http://www.ccleaner.com/ thats good at removing useless files.
If it is a batch file, that means it is just a plain text file. You should be able to open it with notepad or any text editor and see what it is and what commands it will run.