1ª) Uninstall BlackShot using the program "REVO UNINSTALER" in advanced mode for removing all registery of BlackShot from your PC.
2ª) Use the program "Ccleaner" and clean your registery(important) and temporarily files.
3ª) Restart your PC
4ª) Install Blackshot again.
I assuming that your pc have all grafic cards, Direct X and drivers updated.
Also, have some programs that is essential for BlackShot run properly, I will try find to you.