87 Suburban won't turn over/start. Any common problems I should look for?

[Nodnarb76]

Hello all,
I have a 1987 R20 Suburban.
Last night I moved my truck from a parking spot about 100 yards and turned it off. About an hour later went to leave, and when I turned the key nothing happened. All the lights are lit up bright but the truck won't turn over or make any type of noise. Lucky for me I work at a car dealership in the service dept. and the truck acted up at work.
Just seeing if there are any common things to check first so I can point my techs in the right direction.
Thanks in advance!