hey my friend needs my PC, i offered it to him for free but it has to be non functional. or my dad will get me to charge him for it. I dont want to so I was wondering if there was anyway i could rig the PSU to blow the mobo or do some un repairable damage in the PC without affecting proccy, n specially the HD
Does it really need to be unrepairable? How much does your father know about computers and what measures will he take to make sure it is non-functional/ try to repair it before letting you give it away for free?
If it's not much, you could do something simple like take out the CPU power cable to the motherboard. It will just turn on and do nothing.
Or do you really need to something unrepairable? Do you need it to, say, blow up or would you be satisfied if it simply didn't work? You could open up the power supply, clip one of the main leads and put everything back together. Your friend could even salvage the power supply by re-soldering it. Be careful of the capacitors. leave the PSU unplugged for a while before working on it, and even so, careful no to touch the capacitors just to be sure.
If you need it to explode, you would need to see if any of the capacitors have polarity. If any do, they can be installed backwards and explode, if you have access to a soldering kit and can desolder. There's always the chance it could take some components with it though when it dies.
If you are going to be playing the kill the PSU game, definitely suggest unplugging it from the rest of the system except a case fan and using a paper clip to short the green wire in the main connector to a black connector, this will boot it up isolated from any components it could damage.
Easiest option here, charge your mate whatever your Dad thinks is a fair price and give him the money back on the sly (over time maybe), no need to risk injury, death or component damage at all,
Dont try to make a working pc irrepairable, instead find a way round the issue