Make sure your program is updated. This can be done by logging into your desktop product. Select Online in the menu on the top, and then select Check for Updates.
If that does not update your program, you can also manually update your program.
If you are using TurboTax Online, the program should be automatically updated. But if you are still receiving the blank page, try clearing your cache and see if that helps.
Then, log back into TurboTax and follow the steps in this link to get back to your investment sales section of the program.