USB Over Current Warning

I recently installed a new MB and at first my comp wouldn't boot at all. To trouble-shoot I reset the CMOS as recommended in the manual. After this it did boot, however it booted to a screen that said:

USB Over Current Status Detected, Computer will shut down in 15 seconds.

So this led me to find that I had accidently plugged a Front USB cable into the MB backwards. After fixing the mistake, the computer booted fine and has worked since. Both Front USB connections work as well.

My question is this... Does the reception of that error (USB over current) mean that something has fried or is it simply a warning and the MB has built-in protection against that sort of problem? In other words, is it possible to receive that error without having fried something on the MB?

Since all of the USB ports (and everything else for that matter) appear to be working fine, can I assume that nothing is fried?

Thank you in advance for your comments!