Ok Ruth, the 3 fans do not draw power as to heat up your 150W power brick significantly so do not worry about them. Also regarding your hard drive, yes a malfunctioning power supply could help it go the way of the dodo, but that chance is very very small so i would rule it out. It was more probably a matter of coincidence (hundreds of hard drives die every day all over the world with no apparent cause).
Since you are not tech savvy i suggest this as a final solution:
Do not really worry about the brick getting too hot as they are designed to get there and operate within specifications. Keep in mind that i would only trust a BRANDED power brick in such a case, no cheap $10 made in China...
<<<THIS I know enough about electronics to not try! I had bought a 100 watt Targus as a fill in only to have my laptop pop-up a notice that said "Detecting a 90 watt power supply in use". Being as I had paid extra for the 100 watt, needless to say I was ticked off! That was the largest that could be bought locally. What I do have now is identical to the original including the info on the back and saying Dell. >>>
So my final suggestion if you cannot deal with a heatsink-fan on the brick would be to just find a cold surface (aluminium plate or a cold bench or something) and sit the brick on it. The surface should sufficiently remove enough heat. Keep in mind to keep the flat (big) surface of the brick in contact with the surface below. The greater the touching surface, the greater your heat removal will be.
<<<Another good suggestion! Thank you! I'll hunt to see if there's such an animal around here. I'll try all the suggestions offered. I'm sure there's a solution in them and they are all worth trying except for opening the brick! I'd "light up my own life" with that one!!!>>>
Good luck and don't stress too much about it.
<<Thank you, all of you! Your information has been greatly appreciated, along with the time and trouble you've all extended in aiding me. >>
PS: You could also use Windows Power Management features (or HD manufacturer's tools - i know Western Digital have one because i use it) to keep your USB drives spun down while not in use, so while they will be connected they will not draw much power until they need to be used.