Can't instal firefox 4, Gives error that my comupter needs to reboot to uninstall an older vesion. But I have uninstalled the other version and have rebooted 4 times now.

I have a similar problem installed firefox 4.0 update (x86 en-us) am told to reboot all the time. I cannot uninstall and it has also messed up my email attachments which I cannot now open except if they are microsot office.