I have a Windows 7 Home Premium 64-bit SP1, HP Pavillion Dv6. ATI AMD Radeon HD 7400M Series (HP). After installing the latest 15.7.1 driver, I get a message "No AMD" graphics driver is installed, or the AMD driver is not functioning properly." My screen resolution can only be 1024x768 as default (no other choice). What should I do here?