Jar file flashing in new tabs. Security Issue?

When i open a new tab in firefox i get something like jar:file:///C:/users/nameofthePC/AppData…(more) that will flash up then disappear.
When i googled this i came across jar files as a way to record browser info and also came across something about an invisible java app hidden from the user and able to work around security. I reinstalled firefox/virus swept and that didn't do anything.
It flashes up to fast to see the filepath.
Files have been quarantined/deleted that where downloaded recently from websites that have no content and ive never have visited the sites.
Since january 13 there has been 8 intrusion attempts rated high risk by norton all using some sort of http toolkit.
There is also a number of inbound tcp connections blocked- status detected, severity: info.

If i'm mabe a little paranoid blame wired's recent article about hackers.
Thanks in advance for any insight.

Sounds like your computer is infected. Try using more scanners like malwarebytes and spybot and online virus checkers.