So i have all in one pc -packardbell- and i was wondering if i could replace the motherboard with one that has a pcie slot because i would like to get a good graphics card. So i was wondering if all in one pcs have specific motherboards or would any do?
An all in one pc is usually a laptop-grade motherboard mounted to the back of a monitor, so they generally have similar upgrade limitations to laptops. There might be a video input port of some kind that would allow you to use it as a monitor for a desktop pc build.
I think your best option would be to save money and build yourself a real computer down the line. Trying to upgrade the all-in-one models is just about impossible. They are designed down to the millimeter to fit the case and even the cables are not always standard and may be keyed or some custom length.