Power Supply Responsibility help
So a few months ago, the power supply in my HP Pavilion HPE h8-1234 which is my main and I love it, decides to die. It was a 300W Lite-On OEM PSU. The PC was not mine at first, it was my mom's. My dad puts in a EVGA GeForce GTX 550 Ti 2GB, and the PSU does not supply a 6-Pin connector. So my dad cuts apart two of the SATA Power cables and attached to a third party molex to 6-Pin connector that he also cut apart. It does work, but once the PC became mine it starts to concern me. I do a lot more resource hungry task like gaming, rendering, video editing, etc. Sometimes the GPU's fans spin up for no reason when th PC is at idle or sleeping. Then fast forward today, the PC would freeze up, speakers start making weird buzzing sounds, the the computer will turn off. It will not turn back on unless I unplug it, hit the power button and let it sit for 5 or more minutes. Sometimes I have to repeat. So what kind of damage can something stupid like this can do and should I be responsible or not? Thanks!