PU113N

hello, i recently updated my cctv system as I was having problems with the one I had inbeing an old system. what I am wanting to do is access any footage left on the old hard drive. the problems I am having are 1. the dvr will not show on the tv (multiple tvs tried) 2. I removed the hard drive and plugged it up to my laptop but it is not showing up on my computer. is there any way I could solve either one of these problems to view footage? thanks in advance