If a battery is put in backwards will it destroy the computer? Or damage other components?

there is a good possibility that you have rone some damage. however you will need to recheck everything 1st before reconnecting battery. can't help anymore than that.

There's a strap (think there called fused or fusable link)and its there for exactly that reason so if the battery does go in the wrong way or get shorted out at the battery it will just burn that link and not continue through all the wiring.

I did it once in a EB,ECU and all the relays wiring even the fuses were fine-just that one link it started up with no signs of damage.

Cheers Johnny.

It is possible to do a lot of damage but this doesn’t mean you have put battery in correctly then check if there’s any problems including checking your charge rate with a multimeter