Hello and welcome to JustAnswer.
Did you download TurboTax, or did you get it on a CD?
Did you install it and it was working at one time, and just started giving the invalid signature error?
Or did it never work?
This information will allow me to give you a better answer. Thank you.
ACTUALLY I ORDERED A CD... SORRY ABOUT MY FIRST ANSWER OF DOWNLOADING
IT CAME UP BUT IT DIDN'T WORK BEFORE IT JUST DISAPPEARED. THE INVALID
CAME UP AFTER I E-FILED MY FEDERAL RETURN WHICH WAS ACCEPTED BY THE IRS.
IT WORKED ONLY ONCE.
Hello. Thank you for the updated information. Please try this:
Click Start on the taskbar
Click Control Panel
Open Programs and Features
Right click TurboTax 2009, then click uninstall/change
Click the Repair Turbotax button.
If that doesn't work, uninstall Turbotax, and reinstall it. (Make sure to back up your tax files first).
If you used System Restore to go back to a previous restore point, that can cause this error.