NPE dual boot Ubuntu

My computer dual-boots Windows 7 and Ubuntu 14.04. After running NPE (Norton Power Eraser) on Windows 7, I can no longer boot Ubuntu.

 

I have gone into Ubuntu Recovery and restored Grub, but it did not help. Trying to boot Ubuntu just gives me a blcking cursor on a black screen.

 

What has NPE changed in the boot loader that would cause this?