First up, anyone hating on Spiders will be reported, so keep it to a minimum.

My friend has a 150w Spider III and it has worked fine up until today. The channels wouldn't change with the footswitch, so he turned it off and then back on, and none of the lights came on and the display showed little black boxes, something like [][][][][][].

Is his amp f*cked? Or does anyone know anything he can do to fix it? Thanks for any help

Seriously, did he try the factory reset function
I think it's new amp time for your friend.

Not hating, being serious. Sounds like his amp is ****ed. I think there's a way to do a "system restart", check the Line6 website and see.

EDIT: Damn you Sguit

How do you say "I'm okay" to an answering machine?

I believe some people called them "The Little Black Boxes Of Death". I think it means the amp is done.
Jackson DXMG
B-52 AT100
Marshall 1960A
Pedals and stuff
something about "system error" being related to a guitar amplifier makes me cringe. that is something that just... should not be. like digital meatloaf
If your friend cant find any help in the line 6 forums and a system reset doesnt fix things then its time to find a new amp. Diagnostics and repair on a spider would be much better spent toward a more reliable amp.