Hey everyone! I'm new and I am having trouble upgrading my sister's PC. She brought it from Best buy for $250.00 but after buying a new laptop she no longer wants it. I am trying to build a gaming PC and I was wnondering if it would be better to build one on my own or upgrade the one she has left here. Currently the only things I want to keep inside of the original rig is the: Western Digital 500 GB HDD and the DVD/CD ROM Drive The parts I want to add to this: Corsair CMPSU-750TXV2 Enthusiast Series TX750 V2 Power Supply GIGABYTE GA-Z68X-UD3H-B3 Intel Z68 Motherboard Intel Core i5-2500K EVGA 02G-P3-1568-KR GeForce GTX 560 Ti Video Card (I'm a Dreamer and I'm not very experienced) Would this change my software? What should I expect when I install these items? Thank You!