Do u hear it chirping? If not it is dead, sorry. Last time around I had two that were chirping and one even zipped almost the the whole way and both just died not sure why but at this point if you dont hear anything it is not good. So sorry hatching chicks is so heartbreaking
I have to say that I find that they may be alive and not chirping. They sleep lots in between. There are threads on here on how to help a chick out. It sounds like it may be time to intervene. 48 hours is a long time. I wouldn't toss it yet. It might be alive. I think there is a sticky with the information on helping them out on the hatching chicks section. You use tweezers and gently pull back peices of shell until it can come out. Any bleeding put back in incubator and wait a couple hours. Pull it out and see what you can do. Sorry, I hope you find a live chick. Good luck.
We just helped one out this morning. We moved the others out of the bator and into a brooder. We were out for the day, tonight we put him in with the others. His balance isn't as good as his mates, we'll see if he makes it.