I managed to get a hold of a lot of junked computers recently. Many were in really bad condition, but a few almost look new. Of the good ones, are the cases (standard Antec ATX cases) worth keeping? In other words, could I put some new hardware into the old case and essentially end up with a new computer? The main problem I see is thermal, but I can easily cut holes for more fans to solve that problem. Or would there be a bigger problem like new components not fitting properly?