Row of MacBook keys not working.

I've encountered a slightly bizarre problem with my MacBook Pro that I was hoping to get some help with. I was typing when the keys R through O suddenly stopped working. I initially thought there was maybe a problem with the keyboard ribbon but I've noticed they work if I press them in combination with the E key. Does anyone know how to fix this? It's a 2010 MacBook Pro, OS X 10.6.8.

Thanks.