your mazda does have a fuel pump relay, it is located behind the passenger kick panel.
i'm not, however, aware of any fuel cut off switch on your car.
not really under the dash, on the right side kick panel below the dash.
I was just looking through some manuals and saw that there is a switch mid year on the 2000 626 that moved the fuel pump relay to under the hood in the fuse box behind the battery but for most of the year it is under the kick panel.
also, the relay should be pretty small and may be rounded instead of completely square.
With the information you are giving me, is it possible she overheated the engine?
Yeah, sorry to be the bearer of bad news but it is likely that the engine is toast. The good news is that the engine in your car was used for many years in mazda vehicles and also in some fords (probe mainly).
If you are up to the swap, its not a hard one to do as far as engines go and the motors are fairly cheap!
Good luck with the work!
If the engine was overheated to the point that it actually stopped running, its probably going to be best to fit a replacement engine. You can check out the head and you may get by with just having the head re-surfaced and replacing the head gasket, but if it got that hot, there is a signifigant chance that the main and crankshaft bearings suffered damage and you'll be spending much time and money to find out that the engine is still toast. The ignition timing shouldn't be an issue in this case and i'm really not thinking that it jumped main timing either, it just sounds like the accessory belt broke and wiped out the motor with it.