We need help. Please. Related to Lightboost'm.

Here's the thing. After listening to YouTube Masters decided to try the technology Lightboost, in the moniker Asus VG248'E. I didn't like the picture (well too gray). The monitor has 144 Hz in Lightboost'e gives out 120 Hz. I realized that it wasn't the right technology for me. I deleted the program through which, accordingly everything was done and disabled Lightboost but another problem came out. The monitor lost such a resolution as 1920-1080 (144) - it's his native permission and it just does not exist. It is not done. Who came across and something similar was to write off please. I BEG YOU HOW TO RETURN 144 HZ???