So, I'm looking for a computer to run video editing software such as Avid and Final Cut Pro. I'm pretty sure that the HP Pavilion A6750F Desktop PC has decent enough specs, but I was wondering if it's hardware will work properly in OS X for running final cut pro.

2.3 GHz AMD Phenom X4 9650 Quad-Core Processor
ATI Radeon HD 3200 graphics (256 MB dedicated)
RS780M Chipset
8 GB RAM (PC6400)
750 GB Serial ATA (SATA) Hard Drive

It comes with Vista pre-installed, which is kind of icky. Can I downgrade to XP? One of the user reviews mentioned problems with this because of sound card and video card compatibility. I really have no idea what I'm doing, and any help would be awesome.