1. Check to see if there are any scratches or gashes on the touchscreen at all. If there are, then the unit probably needs sent in to have the touchscreen replaced. Call Saltillo Technical Support(877-397-0178) to get a Return Authorization number to be able to get the unit repaired.
  2. It may be that the unit is freezing when it goes to sleep or when you tap on the touchscreen to wake it up. Tap Edit->General Settings->System tab and tap on the Power button and adjust the Time Before Standby When On Battery. Set it for Never and then click on OK  2 times to exit the settings screen. Now use the unit for a week with this setting and just use the I/O Power button to turn the unit on and off and see if that lessens or eliminates the freezing up.