A downloaded file installed a local disk Q that I cannot access or delete. How can I get rid of it?

I downloaded a music file (John Mayer's Paradise Valley) using Frostwire.  The downloaded file was originally 383 MB, and contained both a 55 MB .m4a file, and a 328 MB .mp4 file.  Shortly after downloading, however, the 328 MB file disappeared, and a new local disk Q partition appeared on my hard drive, which I cannot access or delete.  I tried Norton Power Eraser, but it found nothing.  I am concerned that local disk Q contains some kind of trojan or other virus/malware.  Is there any way to delete disk Q, other than reformatting my hard drive?