Originally Posted by TERRIEG
Yep, you wiped out all the Administrator accounts leaving yourself with no easy way to change anything.
You can boot into "Safe Mode" and see if you can create a new Administrator account in there. This tutorial will show you how to boot into the "Advanced Boot Options" where you can select "Safe Mode". Advanced Boot Options
If for some reason you cannot create a new Administrator account in Safe Mode, then enable the "Built-in Administrator account" temporarily while you are in Safe Mode. You can then log off of Safe Mode and logon to the built-in Administrator account to create a new regular Administrator account again. This will show you how. Administrator Account