Keyboard and trackpad sometimes stop working

Hello, i have bought an original MacBook Air from 2008 recently.

Thing is that sometimes keyboard stops responding after I have carried my laptop in my bag (I have a sleeve for it). I had a feeling that it was due to a ribbon cables so I tried taping them down to the body. It worked for some time but when I was in school it stopped.

I have replaced my battery to a new one and I’m wondering how to help it? I need this computer to be carried to school and I don’t know how to make it work so that I can carry it without breaking the connection.

Additionally I have a proof it’s a mechanical problem as when I used the external mouse to restart I checked and there was no tab for trackpad in the system options.

Also I can’t do the PRAM restart despite the fact that SMC works just fine...