Thank you for this! My mother-in-law has been trying to install it for days and spent hours on the phone with Support. She had a CD, a digital download, Intuit sent another CD in case the first was corrupted, then finally she went to Best Buy and bought another one. Nothing worked. My husband went over to help and couldn't get it installed. I googled and found this solution - moving the extracted files to a new C:\TEMP folder didn't work until I instructed him to change the Environmental Variables. THAT is what worked for us.
She was ready to go buy a new computer and pay $200 for Geek Squad support.
