First, your HD 6450 is considered to be legacy (old). AMD doesn't support this Graphic card with updated drivers anymore. The last driver for this card is here (Windows 7 x64): Legacy . From the download page:
AMD Radeon™ Software Support for Legacy Graphics Products
AMD Radeon™ R5 235X, Radeon™ R5 235, Radeon™ R5 230, Radeon™ R5 220, Radeon™ HD 8470, Radeon™ HD 8350, Radeon™ HD 8000 (D/G variants), Radeon™ HD 7000 Series (HD 7600 and below), Radeon™ HD 6000 Series, and Radeon™ HD 5000 Series Graphics products have been moved to a legacy support model and no additional driver releases are planned. This change enables us to dedicate valuable engineering resources to developing new features and enhancements for graphics products based on the GCN Architecture.
Also this from the same link:
AMD Radeon Software Crimson Edition Beta Driver
- AMD Radeon™ R5 235X, Radeon™ R5 235, Radeon R5™ 230, Radeon™ R5 220 Series Graphics
- AMD Radeon™ HD 8470, Radeon™ HD 8350, Radeon™ HD 8000 (D/G variants) Series Graphics
- AMD Radeon™ HD 7000 – HD 7600 (including A/D/G/M variants) Series Graphics
- AMD Radeon™ HD 6000 (including A/D/G/M variants) Series Graphics
- AMD Radeon™ HD 5000 (including M variant) Series Graphics
Applicable Operating Systems:
- Windows® 10 (32 & 64-bit versions)
- Windows® 8.1 (32 & 64-bit versions)
- Windows® 7 (32 & 64-bit versions)
Second you should always use the Full AMD package rather than the minimal when updating the AMD Drivers.
Third: Your Windows 7 needs to be fully updated via Windows update. Your specs doesn't mention if you have Windows 7 SP1 installed on your computer. If it isn't, you will need to upgrade to SP1 for the AMD driver to work correctly.