I have an older box tv that I'm replacing with a flat screen. I took the coaxial straight from the old tc to the new tv and it

[Critchde1]

Help me connect my tv

 

[jsmithepa]

If you are using a cable service, am waging (guessing really because you have provided minimal information) old TV is analog and new TV is digital, if am right you have to ask the cable provider to switch out the old analog set-top box for a digital.

 

[americanaudiophile]

Digital TVs won't tune any channels unless they are detected by the channel scan you do as part of inital set up. Select over the air or cable and start the scan.
The owners manual, as bad as it might be written, is your friend.