The power switch on the PSU or the power button on the case? In either case you probably don't have a completed circuit for any static to pass through.
Anyway, if you didn't feel a static discharge on your finger when you pressed the button then there wasn't any static in the first place.
Have you actually tried running power through it? Has anything happened that's actually given you reason to think something's wrong? And if this happened a while ago, what's made you think something's wrong now?
Basically, you're fine - nothing's happened.