PainInTheTaxes,
You've done the right things and this is a TurboTax support issue and it might well be necessary for them to remote into your machine to do debugging. However, one thing I can suggest is to rename the folder(s) with your .tax* files to something else and see if TurboTax manages to fire up successfully creating a new folder. If so, then one of your .tax* files is corrupt and causing TurboTax to exit ungracefully.
