Why my Vista rating only a 1?

Why my Vista compatibility rating only a 1?
Vista Ultimate 64

COOLER MASTER Storm Sniper SGC-6000-KXN1-GP Black Steel, ABS Plastic, Mesh bezel ATX Mid Tower Computer Case

Antec TruePower New TP-750 Blue 750W Continuous Power ATX12V V2.3 / EPS12V V2.91 SLI Certified CrossFire Ready 80 PLUS BRONZE Certified Active PFC "compatible with Core i7" Power Supply

Intel Core i7-975 Extreme Edition Bloomfield 3.33GHz 4 x 256KB L2 Cache 8MB L3 Cache LGA 1366 130W Quad-Core Processor

COOLER MASTER Intel Core i7 compatible V8 RR-UV8-XBU1-GP 120mm Rifle CPU Cooler

ASUS Rampage II Extreme LGA 1366 Intel X58 ATX Intel Motherboard

CORSAIR DOMINATOR 6GB (3 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Triple Channel Kit Desktop Memory Model TR3X6G1600C8D

HIS H587F1GDG Radeon HD 5870 ( Cypress XT) 1GB 256-bit GDDR5 PCI Express 2.0 x16 HDCP Ready CrossFire Supported Video Card w/ATI Eyefinity

NZXT SEN-001LX Sentry LX Aluminum dual bay fan controller

LG Black 8X BD-ROM 16X DVD-ROM 40X CD-ROM SATA Internal Combo LG Blu-ray Reader & 16X LightScribe DVD±R DVD Burner

Western Digital VelociRaptor WD3000HLFS 300GB 10000 RPM 16MB Cache SATA 3.0Gb/s 3.5" Internal Hard Drive

SAMSUNG Spinpoint F3 HD103SJ 1TB 7200 RPM SATA 3.0Gb/s 3.5" Internal Hard Drive
Ultra ULT40366 3.5" Floppy Drive with Multi Card Reader

Nope, 1 is the worst: http://www.microsoft.com/windows/w [...] index.aspx

That link also gives a walkthrough of what different ratings mean.

To the OP, is your computer recognizing everything you put in? Particularly the RAM? People have been having problems with Vista recognizing full amounts of installed RAM. Your computer should get a pretty damn high rating.

Check that all drivers are properly installed, then rerun the test, most likely a driver issue imo.

I have seen problems with Windows Experience index and HD 5870 cards. It's most likely drivers. Unfortunately you didn't tell us which one was getting what score, but I'd recommend downloading all the drivers off manufacturers websites (e.g. AMD for your 5870) instead of trusting Windows Update. Mine still tries to get me to downgrade my display driver.