Posted by fp4

http://www.bestbuy.com/site/hp-pavil...&skuId=3461058

That's your computer correct?

Buying a slimline computer was pretty much the worst thing you could do. You can take some parts from it but you are going to have to figure out the whole Windows activation thing yourself:

PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i3-4160 3.6GHz Dual-Core Processor ($110.99 @ SuperBiiz)
Motherboard: MSI H81M-P33 Micro ATX LGA1150 Motherboard ($45.99 @ SuperBiiz)
Memory: 4GB (1 x 4GB) DDR3 Memory (Purchased For $0.00)
Storage: 500GB 3.5" Internal Hard Drive (Purchased For $0.00)
Video Card: Gigabyte Radeon R9 270 2GB WINDFORCE Video Card ($159.99 @ SuperBiiz)
Case: NZXT Source 210 (Black) ATX Mid Tower Case ($34.99 @ SuperBiiz)
Power Supply: Corsair Builder 500W 80+ Bronze Certified ATX Power Supply ($45.00 @ Newegg)
Optical Drive: DVD/CD Writer (Purchased For $0.00)
Total: $396.96
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-07-19 19:26 EDT-0400

The parts marked as purchased you should be able to take from your existing computer.