Ever since that major window's patch a few weeks ago my laptop has run extremely slow when it's not plugged in. Before the patch it worked just as well plugged in and not plugged in. What happened? How can I fix this?

As the issue occurred after installing the last Automatic update, I suggest you to try uninstalling the update and check if the issue persists.

To uninstall a Windows Update:

1. Type “View Installed Updates” in the Search box and then click on View Installed Updates – Control Panel from the Search results.

2. To uninstall the update, select it from the list and then click Uninstall.

Then, to prevent the driver or update from being reinstalled, download and run the “Show or hide updates” troubleshooter described in KB 3073930. (Or run the troubleshooter directly by clicking here.) Follow the instructions within the troubleshooter, and then select to hide the problematic driver or update.