oh..........you don't need to reinstall windows to get a higher resolution or more colors.....Most likely you need to check in Device Manager and update the video driver....
try booting into Safe Mode with Networking, then go here:
START>right click "my computer">properties>device manager
next to where it says, "display adapters", click on the + sign....right click on the item in the sub menu and click update...and see if Windows will look for an updated driver for your monitor
If it finds an updated driver, restart the computer and see if you've got more colors