dude, we almost talked this to death in the other thread. if you want to use a computer PSU, itll work just fine, you just need to be mindful of the amperes it output, not the wattage rating on the PSU. There are a lot of DIY videos on youtube on how to repurpose a PSU to use in a home 12v setup, but you need to go about it logically. A PSU outputs DC in a few different voltages. It then splits up the different voltages into smaller leads of varying amperages to feed specific components in a computer that are known to only ever need x amnt of amps at that specific voltage. Disregard everything that isnt 12 volts, put all the 12 volt leads together on one terminal which will "sum" the total amperage to whatever the individual amnts added together are. When doing this, make the leads coming FROM the PSU as short as possible as thin wires dont like carrying the maximum voltage and amperage theyre designed to do for extended periods of time.
For the amount of amperage youre gonna get from a PSU, one of these should work fine. Do the same with the grounds on a different spot on the barrier strip and connect your amp to the respective +'s and -'s along with a remote turn on from the +12v side. If you get a big enough PSU, you might want some distro blocks, perhaps even one with built in fuses, as youre going to want to fuse it anyways. Beyond that, youre going to want to get an AC to DC converter which arent cheap. If youre just wanting music in your house, you really should look at a receiver for the mains and if you arent going to go with a home sub thats already powered, and want to use your car audio gear, then getting a PA amp for the bass is ideal.
Such as this