I have Ubuntu 18.04 dual booted with Windows 10. My PC Specifications are:
Processor: Intel Core i5 4690 3.5 GHz with Turbo boost upto 3.9 GHz
Ram: Corsair Vengeance DDR3 8GB clocked at 1600 MHz
Motherboard: Gigabyte B-85M D3H
Graphics Card: Zotac GTX 660 Synergy Edition 2GB
HDD: Western Digital 1TB Caviar Green WD10EZRX
PSU: Corsair VS650
Ubuntu works fine when I run pre-installed applications like Firefox, Libre Office or when I work on the terminal, but when I install and launch some third party apps from "Ubuntu Software", like Spotify, Stellarium, Chromium etc, my system gets completely frozen like mouse and keyboard not working and the only option I have is to restart my pc or trying "ALT" + "Print Screen" + "REISUB". What is wrong here? Any help is appreciated!