Question : Problem: Computer is EXTREMELY HOT

We recently had the power supply/fan replaced in our desktop tower.
This computer was idle all day, when
we went to use it tonight a distinct hum was coming from the back.

When we checked the fan it was turning but the back of the machine
was very hot, almost as hot as a stove top. There were both a ZipDisk and a floppy
in there respective drives and when we took them out they were very warm to the touch.

The processor itself has a very powerful fan that sucks air through a funnel through a grill on the
side of the case. That fan is running fine, guess it saved us.

The machine was custom built about three years ago, it runs DOS for a custom application the company has been using for years. There were no error messages of any kind.

What could be going on? Did we get the wrong power supply as a replacement?

Answer : Problem: Computer is EXTREMELY HOT

you can post pictures of the inside, can help
but as said above: a pS too small (i doubt it) or a bad one (new can be bad)
can you test the PS on another system?
>>   We recently had the power supply/fan replaced in our desktop tower   <<  Why?  this can give more info on the actual problem