For about a week I have been getting the following message on start-up and Windows (XP Pro) has fully loaded "Error loading C:\Windows\difxshs.dll Access is denied". I have searched for that file to check its permissions but it is nowhere to be found (and yes I did enable hidden and system files). Also the screen dims and brightens for several minutes. Additionally, I am getting new browser pop ups of IE7. All windows update are done. Doing an AV scan has revealed nothing.