I would use Adobe's dedicated Flash Uninstaller;
http://kb2.adobe.com/cps/141/tn_14157.html
Remove Flash, (it may remove it from IE as well). For good measure, reboot the computer afterwards, then re-install Flash;
http://get.adobe.com/flashplayer/
Be careful with that 2nd site. I see it now includes a "Free McAfee Security Scan (optional)". You may want to untick that.
Mark
I re-installed Vista and Firefox 3.5.7 on my Toshiba laptop and anything that requires Adobe Flash Player will not work. I have tried installing the plugin but still can't get it to work. Flash will work in Explorer 8. Can anyone offer any help. I would much rather use Firefox over IE

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