Need help ASAP

So, I got hired with little notice over in the Seattle area (Everett), so I packed up all my stuff and I start tomorrow at 6:00 AM. I stayed at a friend's house in seattle last night... made the 150 mile trip here with no problems at all, started and drove around seattle no problems at all yesterday after I was here.

Went to turn it on today... and it sounds like the engine's seized. Any ideas?

It's getting electricity because it's trying to turn over... but it doesn't sound like the starter's moving, and the belts don't budge. Gas isn't the issue because it would still turn over, it just wouldn't catch. I just got an oil changed 2 days ago before the trip, oil's still full and clean, no burn smell... so I didn't blow a gasket and dump my oil... It sounds like it's trying to turn, but something's physically stopping it... either in the starter or the motor itself... But... how would that happen overnight while the car's parked?

So... any suggestions as to what that might be... or, if anyone happens to be in the Seattle/Everett area, any suggestions for where I can get it towed to that won't rip me off?

No fluids under the car, and it started perfectly until just then... so sudden catastrophic failure... while parked... over night?

I did notice my gas cap was lose, but I didn't see any residue from anyone dumping anything in, and I still have a full tank, so they didn't siphon it out. I assume I just left it loose when I filled up.... but that doesn't happen much. And the same car's parked next to me this morning as was there last night. So, if someone just randomly decided to pour sugar in my gas tank or something, I've heard that's bad, but I have no idea what it actually does... But I'd imagine it wouldn't stop it from cranking completely.