mozilla fire fox help

timetunnel

hi
have this problem about a month or so , just thought it might be a problem with the hard drive , but last night got some time to mess around with the computor , you know how it is , no kids around ,
when ever i try to update my fire fox , i kept getting message

your computor must be restarted to complete a previous upgrade of fire fox , do you want to reboot

which i did ,
but when computor came back on the same thing would happen .
i gave up , did not think much of it as fire fox which i was using seemed ok
then i noticed the the flag at bottom of the screen , which in formed me the my windows security was disabled ,
i tried to switch it back on to no avail .
even googled to make sure i was doing it correctly .
so i thought it might be my antivirus , checked that .
but when i tried to udate the antivirus ,
i got the
mozilla fire fox message telling me my computor must be restarted to allow a previous upgrade of firefox .
so last night i went into uninstall programs and uninstalled fire fox in the admin , which seem to have removed it , i then went into the other part of my computor , the guest , went into uninstall program and saw the firefox had being removed , but there was still an install folder showning for morilla fire fox . so right clicked to uninstall ,
but got the message telling me ,
your computor must be restarted to complete previous upgrade of firefox,
how do i get rid of it ,
it has to be a virus , i have scannned with spybot and alivira
all help appreciated .
thanks in advance