On a rare occasion, it might become necessary to manually remove residual QuickBooks installation files and folders left behind by the Microsoft Add or Remove Programs utility. Performing this procedure and then reinstalling QuickBooks is often referred as a "clean install" and is a technique used for isolating or resolving problems with QuickBooks.
Caution: Performing a "clean install" of QuickBooks will require all other Intuit software applications that share the same installation folder to be reinstalled.
It is also advised to back up your company file to a safe location to prevent it from being accidentally deleted or overwritten. For more information, please refer to the article Back up company files overview. Please be sure to have your QuickBooks installation CD-ROM and license key handy before reinstalling QuickBooks.