As a QB user for over 5 years or so, I can vouch for the given steps that they are extremely helpful when the user has to find QuickBooks Validation code in Registry. Check them out.

• Go to QuickBooks Desktop and make sure not to open the company file or be it left open.
• Now go to Help Menu and select About QuickBooks.
• A prompt window shall appear with your product’s registration details.
• Press CTRL+R+P and fill the required fields with the validation code.
• Click on Next to complete the process.

Read more steps on the issue by clicking here. Meanwhile, call on xxx-xxx-xxxx and get the best immediate support on the error anytime.