been off PT for a while, now back and have issues.

Hiya All. Its been ages since ive been here. As per bloody usual every time i go to record something happens. Tried my tape machine today and the heads are sooo dirty and now im in PT and the issue here is heavy crackling if i try to lay down a track. It also causes the other tracks that were previously recorded years ago to crackle as well.

Im using old PT 8.05

IMac 2007 model with 4GB ram and SSD

Anyone have any tips?