Sorry to hear about the troubles.
If you hooked the second screen with the HDMI monitor and works, the first monitor the issue probably comes with the cable you are using.
Deinstalling the drivers please follow these steps;
If you have issues after installing AMD driver suites, this is one method you can try.
To perform a ‘clean install’ of AMD graphics drivers:
You should make a system restore point before attempting, just in case
1. IMPORTANT: All Windows Updates should be current, including the ‘optional/suggested’ updates
2. IMPORTANT: Disable all anti-virus/ad blockers/anti-malware/ anti-anything before trying to install
3. IMPORTANT: Netframework is required and must be the latest version. (from Windows Update)
Download the drivers for your computer to the desktop. Follow steps 1-5 ( http://support.amd.com/en-us/download ).
Do not use ‘auto-detect and install.
Delete existing drivers from your computer:
In computer control panel select ‘uninstall a program’
For computers with Intel processors:
Select AMD install manager and choose ‘express uninstall all AMD software’
Including the install manager.
For computers with AMD processors:
Select AMD install manager and ‘custom uninstall’ the graphics drivers and CCC only.
Reboot into ‘safe mode’
In safe mode run Guru 3D’s DDU
Install the new driver suite.
NOTE! Certain laptop configurations are not compatible with AMD’s Mobility Catalyst™ Driver.
AMD provides graphics drivers for most laptop brands and models for the Mobility Radeon™ HD series of graphics cards.
If the AMD Mobility Radeon Driver Verification tool reports that the hardware is incompatible, then the notebook manufacturer is the exclusive provider of the graphics drivers for your notebook. (GPU-28041)
Sony, Toshiba, and Panasonic will not accept generic drivers. Get drivers from manufacturers support site.
Laptops with ‘switchable’ graphics must use manufacturer supplied drivers.
Also note that some users had some issues with this Microsoft update kb3004394
You can uninstall it to verify if this is causing the problem.