Windows 7 HDMI Issue - Switch to Projector only, now stuck

Question

PLEASE I AM SO VERY STUCK.
My father told me to watch Netflix while I was home from university - using the new HDMI Cable we purchased - very proud that he had figured it out on his own. So I turned the TV input to HDMI, and, after loading my selected movie, plugged the cord into
the laptop (A Lenovo B575). It worked! I saw the Netflix loading screen on BOTH computer and TV. Great! BUT, the bottom few inches of the picture were cut off on the TV (An LG 32LN530B), so I decided to change the resolution a bit. I went into the control
panel to adjust and went too far - I forget now the resolution I chose, but I increased it. The TV then said "no input" as if no HDMI cable was there. I had closed the control panel while the screen was adjusting, and so I hit Windows+P to open
up the "Projector" modes, thinking this would bring me back to the same place.
Somehow, I mistakenly switched the output to "Projector Only", and thus the laptop's screen went black (black, not blank as if there were still a backlight). As there was no input for the TV because of the improper resolution, and no output for
the actual laptop monitor as it was configured to be projector only, I figured as soon as I unplugged the HDMI cord the screen would come back on. No such luck. I waited, and then after a few minutes decided to try Windows+P and blindly readjust. Still
no luck. I tried many combinations of the arrow keys, wait times between Windows+P and arrow keys, etc. The lights of the keyboard are all functioning completely normally, but don't seem to be responding to the controls. I also tried Fn+F3 (the equivalent
of Windows+P)... to little avail. I then tried Function and F2-F6 (all of the keys with orange 'functions'), respectively. Still nothing. To reiterate, no HDMI cord is inserted, computer is running perfectly, and both Windows+P and Function+F3
tricks failed.
So, I restarted my computer and logged in again, successfully getting to the desktop. I tried to plug the HDMI cord as I had done initially, when it was all working properly, and - screen goes black again. It's as if it remembered that I set the secondary
or alternative display resolution to be higher than possible and on projector only. I tried everything again. I repeated this quite a few times, using different combinations. Still, the black screen remains. I went into the control panel again, to see if I
could adjust the resolution of the TV (secondary display) BEFORE it was connected. No luck. It would only let me adjust the resolution of the computer. After spending an excrutiating hour googling and finding no help anywhere, I tried to consult the TV's owner
manual. No help. I adjusted all the proper HDMI settings on the TV itself, and it still is causing the black screen.
I am hoping there is some way to make my computer "forget" the HDMI settings so that it will work as it did initially, before I got cocky and wanted to adjust things. Somebody, please help me. It's now 2am.

Answer 1

press F8 and choose "last known good configuration"
if doesn't help, try to remove your amd display and reinstall again
http://support.lenovo.com/en_US/downloads/detail.page?DocID=DS025425
if doesn't help, please try system restore