There has never been a Firefox 1.7.8 release, ever. Your "scanner" is most likely buggy and "finding" things that don't exist.

http://www.oldversion.com/windows/mozilla-firefox-1-7-8

Is this not it?

No, that's some fake version. If you look on ftp://ftp.mozilla.org/pub/firefox/releases/ you can see all versions of Firefox that were actually released. There was a Firefox 1.5 branch, and then a Firefox 2 branch. Never was there a 1.7 branch.

Interesting. I'm running a couple of virus / malware scans to see if maybe this is the case. I've also opened a support ticket w/ the vulnerability scanner vendor. Will follow up w/ my findings.

Thanks for your support.

This is well outside any area of expertise that I have but there was a Mozilla(Suite not Firefox) 1.7.8 released in May 2005. Is it possible that you could have that or some residue of it?

There was also a Password Maker 1.7.8 for Firefox.

All of this seems unlikely on a Windows 7 computer so unless you get some help from the scanner forum or other scans I would be inclined to ignore it presuming there is no obvious continuing problem.

Does the scanner give the physical location on disk? In older versions of Secunia PSI you had to switch to a more advanced reporting mode in the product to get the path information; not sure if that is still true. The install folder or other context may help solve the mystery.