Mozilla/5.0 (Windows NT 6.1; WOW64; rv:9.0.1; sv:4; id:FFF79A8D-EC94-58C6-BA9C-9BCE5DD45C10) Gecko/20100101 Firefox/9.0.1 It shows running a Mozilla Browser in the series 5 versions NT 6.1 = Windows 7 Wow64 is a Windows file The rest of that is RV (revision) 9.0.1 SV no idea Id looks like a registry entry but google turns up nothing. (if ISP found that then could be a serial # to the Firefox but..do not think so and would not help anyways) Gecko is Mozilla and I think the Engine version We would suggest : https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware Please let us know if this solved your issue or if need further assistance.