If the PSU didn't die due to a fan failure, the fan(s) may still be usable for something else (e.g. as a case fan). May require a little creative connector splicing, but that's no big deal.
Caveat: If you ever poke around inside a PSU, please exercise caution around the high voltage caps. They can have hundreds of volts of charge on them even if the PSU has been off for a long time! First thing I do once I've got access to the underside of the PCB is short all the large caps by momentarily bridging their connections with a screwdriver, to make sure all of the residual high voltage is discharged. Edit: And if you don't know what that means, you probably shouldn't be opening up your old PSUs...
The years just pass like trains. I wave, but they don't slow down.
-- Steven Wilson