Some time ago I noticed that I couldn't run any Adobe software anymore - removing and re-installing didn't help either. As soon as I would try to run an .exe file connected to Adobe there was a window that said:
"Windows cannot access the specified device, path, or file. You may not have the appropriate permissions to access the item."
Now the same message appears with other files too, especially setup files and updates (for example TeamViewer, Java or Avira Antivir). It also appears when I click on "change firewall settings" in the Windows XP security center. I'm logged in as the administrator though, and the message also appears when Avira is disabled (when I try to start its control center nothing happens at all).
What's the matter? I would really appreciate your help!

