After my computer has entered its power-save mode, pressing any key on the keyboard will bring it "back to life" and I am then prompted for a password. I very carefully enter the password but am repeatedly told that the userid or password is invalid. The only way I am able to successfully log back on to my account is to select 'switch user' as if I am going to log onto another account, then take the 'switch user' option again back to my account. I am then able to get back to my desktop.
What could be causing my computer to determine that my password is invalid initially upon 'waking up'?