I tried to hook up an aux fan..from a older computer. Low amp 12V...

I found a 12V "plug", not an aux fan plug, but from one of the extra power supplies for a drive, I tapped into that, when I started up my machine, the main fan sounded like it was going to spin out of the box....I disconnected the aux fan right away...which appeared to be running good.

I cleaned the power supply fan and the video fan(which was clogged)..
did that possibly cause it? 

Stupid Q...where exactly should I tap into? Does it matter where?

Any ideas?

Dell 8400 3.4Ghz
4G Ram
Nvidia 6800@256mb...soon to be upgraded! (Ideas here?)

Thanks in advance!

(edit)

OK

Sorry all, just being careful......I guess it was a simple thing to figure out...