I began to have printing problems which may have been triggered when printing from the Firefox browser. I did not isolate the trouble with Firefox, but I did determine the cause was an installation of Windows Internet Explorer version 11 which was installed automatically on a Windows Update. I am running 64-bit Windows 7. I determined V11 was the problem by removing updates one at a time then printing from several programs I use like WORD, Excel, Powerpoint, Adobe Reader, Firefox, and Thunderbird. The symptom of the problem was that I could print fine once or twice, but then the communication between the PC and printer (Lexmark S405 b/g) became busy and no other print jobs would complete, even those from two other PCs (neither had V11) that worked fine for printing any print job before an attempt from the PC with V11. Once I resolved the problem to be V11, I did not try to isolate if it was triggered by any print job or one from Firefox, but I a little suspicion that it could be triggered by a print attempt from Firefox since I know I was able to print once or twice before the problem was triggered.