You can use the screen for video if it has video inputs. However, you wont be able to use the touch screen to control your pc.
im new to the car pc world and am wondering if it would be possible to set up a car pc to use a pioneer touchscreen?
is it possible to ise the touchscreen with the car pc or will i need an overlay or a special screen?
If you can get composite (the yellow RCA type connection) video to the screen from your PC, then you can use your Pioneer unit as a monitor.
Video quality will lose quality, as PC displays weren't meant to be displayed on the resolution of a television, which is essentially what that Pioneer screen is.
You will not be able to use the touchscreen without serious modification & reverse-engineering of the workings of the Pioneer unit. For most, this is not worth the effort or expense.
It is always recommended to get a screen with a VGA input for the best possible image quality from the PC.