Starting issue -possible ground wire/battery terminal
 

I have a problem with my 2005 civic ex coupe. So first of all this might be a little long but let me explain the issue. I bought the car a month ago, I have only driven it 4 times total and have already had 2 occurrences where it wouldn't start. The guy I bought it from said he has had issues with ground wires in the past but said it has been a few years n he thought it was fixed. So I took it to a shop the first time it wouldn't start n he said some of the ground wires and terminal were loose so he tightened them down and also tightened the battery down, two days later I start the car let it warm up go back out to it and it's running but my radio is off and all gauges are at 0 or dead like the car isn't started( but it was running) I didn't know what to do so I tried to see if the terminals were loose or the ground wire connections and from what I found they were still tight . Went to try again and it started somehow even though I didn't tighten anything. I tried again today and it started just fine again...so idk what the issue is because I didn't really do anything between it not starting and starting again, anyone with suggestions