[Solved] PPSSPP causes computer black screen

[Tabman]

It probably has nothing to do with ppsspp, but it rather sounds like you increased the refresh rate or resolution beyond the safe range of the monitor. In that case, in order to avoid damage to them, the monitor refuse to work. Of course, if they refuse to show anything under windows, it's rather hard to set them to something safe.

Anyway, boot your computer and, after the bios info vanished, press F8 (you probably need to do this more than once, just reboot the pc again).
This should give you the something like this screen:
   
select "enable low-resolution video" and you should be able to boot into windows and change the resolution/refresh rate to something working.

And yes, this is completely off-topic