Is the battery dead? You don't give anything in way of details so try going to the start button on your computer. Click on it and then select ProSeries. Click on "repair updates". See if that does anything for you.
You may want to start from the beginning....
Did you download and install previously and everything worked as expected, now suddenly it doesn't?
Or what was the order of events that youve gone through up to this point?
Also, go to your installation directory, look in /32bit and make sure you have these two files:
if you don't, double check any anti-virus programs like AVG. This happened to someone yesterday - it quarantined protax20.exe and it just wouldn't run until the user went into their AVG Admin Panel and listed the ProSeries directory in the "Exceptions" panel.