This one is a cool device that can do it. The technology by which it works seems a bit suspicious, but the site appears to be legit as well as customers' reviews on amazon. The good thing about it is that you can use any object to mediate the touch, so you could use the stylus to draw. Judging from how the technology works you probably don't need to actually touch the screen, it's enough to approach it close enough.
The dilemma here is that if you'd use the stylus to draw on your computer screen often by actually touching the screen with it, you might scratch or otherwise impair it. On the contrary, if you wouldn't actually rest the stylus on it, then it might be a bit inconvenient also, you'd always have to mind the distance, your arm might get tired more easily and the drawing process wouldn't be as natural as with actual touch.
So it would be better to have a specialized additional layer of film stuck to the computer screen (magnetic or otherwise) which you could actually touch with the stylus and which would react to the pressure and through a Bluetooth or USB connection visualize the movements on the actual screen. Something like this. Just that this one is most likely a scam. The whole company appears to have no substantial online presence. But I might be wrong.
If the latter device is not yet developed, it seems like a good idea for a startup company. The only problem with the latter approach is that you'd have to paint on a vertically oriented screen (having in mind ordinary laptops), but it could be leaned back and rested on some specialized frame, just like many tablet computers.