If you do not want to install the software to your computer why did you purchase desktop software?
I thought they're selling the register code or something like that. Many software companies do this to have you download by yourself and then just enter the registeration code.
To call TurboTax customer support
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They are available from 5 a.m. to 9 p.m. Pacific time.
The desktop software to install on your own computer, and the online website, or completely different products. You will need to return the CD to Costco and then pay for the online product when you check out and file. TurboTax customer support might or might not be able to apply the cost of the CD to your online account.
Incidentally, the desktop program is significantly more powerful than the online program and is more cost-effective if you are self-employed or if you have more than one return to prepare.