MSI Wind U100 monitor

Hey folks, newbie here.

I acquired a MSI Wind U100 and using the instructions found online installed the Mac OS on it. I couldn't do it all myself; I needed help doing it correctly, so I've obviously missed some important instruction along the way.

The machine has worked fine. But just today I installed the updated Mac OS via software update, and when the machine rebooted I found my display image was distorted: stretched in width. I had lost my 1086 screen res for 800x600 only. This was something that happened on startup previously: the Apple image on startup was distorted in width. But by the time the desktop booted up the screen rendered correctly.

A friend suggested I needed to reinstall the monitor kext file. I've been doing some research online, but haven't found a lot of information on whether that's correct, or how to do it.

Any advice?

All other operations run correctly.