Computer account disabled?

Two machines in two days failed to login with “Domain not found or Computer account disabled” message.

I logged on as local admin and got IP address, internet access, etc.

Active Directory Manager did [b]not[/b] show computer account disabled.

I fixed it by:

From the computer, remove from domain, restart, rename computer, restart …

From Active Directory Manager: create new AD computer account, delete old account …

From the computer: Join domain, restart, rename computer to old name, restart.

What causes this? Is there an easier way to fix it in the future?