can't play any video after i used two monitor

[goofy08]

my computer have just 1 monitor and i can play the video very great
after i use hdmi cable to connect my tv (2 monitors),i can still play the video
now the problem is: if i don't use my tv (disconnect the hdmi cable) and even i reboot my computer,i can't play any video
it cannot let me turn on the GPU,and i just see the dark screen when i play the video,but it can play the sound only
i've try if i connect back my tv (that means if i use back to 2 monitors), it have no problem any more

please help to solve the problem
sometimes i just want to use one monitor to watch video

sorry about my english is bad
and thank you so much for your help

[Ghost]

Please go to Splash installation directory and try running Splash CleanStart.

[goofy08]

Please go to Splash installation directory and try running Splash CleanStart.

sorry
it didn't work

[Ghost]

Please check the NVIDIA control panel if there is only one display set up.
You can also check to run the multi display setup in clone mode and check if this solves a problem.