You have two GPUs in your PC.
The HD 7xxx GPU card and the APU Processor with IGPU.
Do you get video output during POST or BIOS from either the GPU card or Motherboard video outputs?
Try connecting your monitor to your Motherboard's Video Output and see if you get any video on your Monitor.
Generally if you uninstall the GPU's graphic driver from your PC, Windows will automatically install MS BASIC DISPLAY ADAPTER driver so that you will get video output while finding or installing a new GPU Driver.
Either your GPU card is not being seen by BIOS so BIOS made your IGPU the Main Display adapter instead of your HD 7xxx GPU Card or your GPU card is defective or you installed the wrong AMD driver. That is why I suggest you connect your Monitor to your motherboard's Video Outputs that gets its signal from your APU IGPU.
Or remove your GPU card and see if you get video output from your IGPU Motherboard video outputs or not.