I can totally relate. I spent two whole days on my (NEW) PC trying to figure out how to correct the same problem... "windows installer could not be accessed...error code 643) !!
It can also come up with different error codes. anyhow, to cut to the chase, I ran accross this solution somewhere online in a forum on Windows and IT WORKED!!!!
Try it. I don't know exactly how this guy
figured this out but it definitely fixes the problem. From all the replies he was getting, it worked for a bunch of people having the same problem!
1) At Start type: regedit
Lft Click on: HKEY_LOCAL_MACHINE
Lft Click on: SYSTEM
Lft Click on: Services
Lft Click on: MSIServer
Rt Click on: WOW64, select Modify and change
value data from 1 to 0 (zero)
2) At Start type: run
Go to Windows Installer and stop and start the program.
3) Reboot your computer.
Now go and try and do an install. In my case the steps above took all of 3 minutes and i went to the application .exe file I was trying to install and it installed perfectly, not skipping a beat...everything since then has installed perfectly!
I'm curious to know if this works for you. Please let me know OK. Margie email@example.com