Does your computer meet the system requirements?
TurboTax 2017 Minimum System Requirements
Customer support will available on Tuesday after the long holiday weekend.
To call TurboTax customer support
They are available from 5 a.m. to 5 p.m. Pacific time Monday-Friday
Did you maybe buy the Mac version? Call support. Did you try turning off your anti-virus program to download it?
Contact Customer Service (they might be closed until after Labor Day)
5am-5pm Pacific Time Monday -Friday
What is the Turbo Tax phone number
How to Download