Hi my name is ***** ***** I will be the expert working with you today to help resolve the problem you have posted.
you are trying to open Picasa on which device.
when was the last time picasa was working
sorry about the delay.
For windows 7
click the windows menu button select search
type in system restore and hit enter.
Now the system restore dialog box will open.
click the round circle like radio button which says choose a different restore point and then hit the next button
on the next screen or box you will see a check box at the bottom says show more restore point.
Click on it to put a check mark on it you will get many old dates
click on one of the old date and hit next and now hit finish.
The computer will restart on its own while it restart please do not interrupt it will take around 10 mins to get you back to working windows without any problem.