How to connect CPU to laptop monitor

you can expect, however the information you've provided is very poor.

so here goes...

CPU cannot be connected to a monitor as there's no interface for cpu to vga.

assuming that by cpu you meant a desktop computer, then, connecting that to a laptop screen is very unlikely. Basically, it will be possible if you laptop had a video in port, but since majority of laptops don't have that feature, again you're most likely out of luck for the easy solution. but doesn't hurt to check

there is an option to take the laptop apart, take the screen off and by splicing the wires into a vga socket you could connect it to the desktop vga port. there's however a problem there, I'm not sure how you would go about separating the power for the lcd from the actual vga leads.

If both your laptop and desktop PC are connected via a network you can remote desktop from one to the other