Windows Based Computer Shop Billing Software

I need a comprehensive billing software for my computer shop. The software has to be a Windows compatible desktop application. Key features should include:

- GST Integration: The software should handle GST calculations and invoicing seamlessly.
- SMS Notifications: I need an integrated SMS feature to notify customers about their order status or any promotions.
- Barcode Based Product Search: The software should have a barcode scanner compatibility for product searches and inventory management.

In addition to the above, the software should include a licensing feature, requiring yearly renewal. Inventory management is also a key component.

Ideal skills and experience include:
- Proficiency in Windows desktop application development
- Prior experience with billing software
- Understanding of GST regulations and integration
- Knowledge of SMS API integration
- Experience with barcode scanning software
- Familiarity with inventory management systems