🚀 go-pugleaf

If you are saying that this has been an ongoing problem with Reader 7.0.5, then the install did not go as intended. We will assume that you have XP w/SP2 fully patched. We will also assume that the PDF files are known to read properly on another machine. If all of this is true then you need to do what follows, IMO.

You really need to uninstall both versions completely to start with. Use Add/Remove Programs for the first step. Check and remove the folders for Reader as well. You can also run Windows Cleanup utility as well. The most difficult and potentially dangerous part is to edit the Registry-to remove all of the left over references there.
WARNING-editing the Registry can be dangerous. You do this at your own risk!
Now you can try installing Reader 8.