Yeah nothing wrong with using Windows Update. it'll update to service pack 2 for instance if you haven't got that yet (if your on XP), Otherwise it'll just update what it can depending on what Windows you have.
If you have a slow connection though, it might be best to only select to install one thing at a time usign Custom and not to install the whole lot in one. if you have broadband or something it's okay.
As for that, it seems something to do with the monitor settings...
Some video cards in settings (right click desktop, Properties) in Advanced sometimes have position values which you can move left and right, up, down instead of using the monitor to do it.
if you change these instead (if it has any) to get the right position in there, it might save the settings since it might be to do with windows more than the monitor and yuor video card just resets the amount every time
Hope this helps