|Probably it is a virus. Check whether there this file "autorun.inf" in your shared folder P:|
For me, there was others strange files name at the shared folder's root with the following extensions: .lnk, .dll and .exe
My server is SAMBA, so a I make a script that checks whether "autorun.inf". If it is found, then it cleans it and all other lnk, dll and exe strange files - just at the shared folder's root.
But at first, I stopped the sharing service, reinstalled the OS in all machines that had this "link" - because, at that moment, none antivirus nor antispywares recognized any virus or spywares (it was 2 months ago). Even using HijackThis all entries was ok for me.
I hope this help you.