Open the PC on a machine with ADO 2.5 on it and open a VBA screen. From the menu select Tools/References and find the Microsoft ActiveX ADO 2.5 option and make sure this is selected. There may well be another option for ADO 2.7 that has the word MISSING in front, unselect this option. Compile the VBA and correct any code with errors in it. The database should be ok after this.