after following hours and hours instructions here, at mircrosoft knowledge base, microsoft technet and install shield consumer central, the error would not go away. Some of the instructions could not be acted on because i did not have the file locations they were talking about. So i searched my laptop for comparison. i found that my msiexec.exe was located in windows\system32\dllcache, one directory down. but in the system32 folder i had a file named msiexdc.exe. It has the same properties as the file in dllcache. i copied the correct named file from dllcache to system32 folder and windows installer worked. have not a clue how that would happen.