The problem did not occur if Firefox was already running.
Some more advanced users were able to cure the problem with a registry edit, others like myself were reluctant to go that route and lived with the annoyance.
Last night i downloaded Firefox 3.6rc2. Problem has gone away! Seems way faster also. Sometimes these program issues can make you crazy and angry!
This is still a beta version with some known issues but i have not yet encountered any bugs.
Edited to add, no problems with browser slowdown after lengthy time viewing videos or multiple windows.
Edited by goldhound, 20 January 2010 - 02:52 PM.