Hi there, so I recently got a 2008 Mazda 3 and I noticed the air filters needed replaced. I followed this guide (https://howtune.com/articles/163-cha...er-on-a-mazda3) and everything went smoothly. I put everything back together and the car was running smoothly, when suddenly the radio stopped working and the lights flickered, now I can't get the car to turn back on.

I figure something must've happened when I removed the fuse box, but I'm not sure what it could be. I've since removed it again and reinstalled it, but still nothing.

 

There isn't any need to remove, let alone touch the fuse-box. Possibly a loose connection or blown fuse/fuses. I suggest you get a professional to look at it. I get the impression your not car savy.

 

like the reaper said, check for loose connectors or a loose ground.

 

Just look around where you were working to see if you ended up loosening any connections.