Older computer memory trouble

[sanddrag]

I have a system that I think is a Celeron 700. It was a nicely functioning machine. It has two memory slots. Here's where the story begins. The computer is just full of dust beyond belief so I blow and vacuum it out. Them, I take out the single stick of 128mb PC133 memory out of it (the other slot is empty) for use in another system. I then install a stick of 32mb PC66 memory into each of the two slots. I power on the system, I get no beep, no video, and a strong burning smell. I quickly disconnect the power and remove the RAM and see that one pin in one of the RAM slots is burned/melted and so is the corresponding pin on the stick of memory.

What did I do wrong? Are you not supposed to use PC66 memory in a PC133 system? Did the dust get in there and short something? Was there a jumper I should have moved but didn't?

I'm afraid to put the original PC133 128mb stick back in there for fear of damaging it.