I have a HP Media Center m7334n desktop. First I ran into a trayapp.msi file that Windows Installer kept trying to find on my PC. The path was missing and the file could not be located. An installed software was removed maybe from a program I tried to download and uninstall. Now I have Windows Installer trying to find a HPproductassistant.msi and can't locate it. I have to alt-cntrl-del to stop it. I have not installed anything on my PC or removed any programs. What could be causing this?