Firefox 4

If I type into any input boix while in firefox I find the text is reversed and also the cursor will scan backwards through any text such as an email in reverse in the open window. It will flash through each tab in the startpage . If I start as an administrator this does not happen. How do I cure this? I have tried uninstalling and reinstalling and looked I task Manager for any freak processes. There is no sign of malware or virus.