Is this a new laptop that came with 8.1 preinstalled? Please either post your system specs here or fill them out in your profile to better help you.
To remove an update: WinKey/X > Choose "Control Panel" > Choose "Windows Update" > Choose "View update history" > Choose "Installed Updates" link > Choose an update and right click > Follow instructions. If this works, we'll install updates one at a time to see which one messed things up.
Along with David's solution above, make sure that you backup important personal files before restoring. There should be an OEM hotkey upon boot to enter a menu screen for restoring.