I can confirm that this worked on my PA3553.
My laptop first started not booting and only booted after being left on blank screen for a while. It was intermitent, and then it became constant. My laptop stopped booting. The fan would come on, the camera led would go on/off with Fn+F7, but no boot, no POST.
I had the CMOS battery replaced, nothing.
And then I did what was suggested on the video. It worked!!!! Many many thanks, I am typing this from my resurected laptop. It should be the Video chip that needs floating.