Hi peteski72,
Have you tried restoring your system to a time just before you upgraded Firefox - Start, All Programs, Accessories, System Tools, System Restore.
If you don't see your Start button, press Ctrl + Alt + Del (all together) to bring up Task manager. Go to File, New Task (Run) and type the following command:
C:\windows\system32\restore\rstrui.exe
then click OK.