As dell seem to have errored by making it possible to downgrade the cpu on this ecode you can jig things about a bit to get a quick system with Vista Ultimate for a good price.
Select the 1.86Ghz cpu as listed below and Vista Ultimate.
As usual reduce the warranty to 1yr and of course buy via Quidco for cashback savings too
305-D02922 Now £687.44 or less delivered
Intel® Viiv Core 2 Duo E6300 Processor (1.86GHz, 1066MHz, 2MB)
English Genuine Windows Vista Ultimate
Dell 20" Black Wide Flat Panel (E207WFP) - UK/Irish
2048MB Dual Channel DDR2 667MHz [4x512] Memory
320GB Serial ATA RAID 0 Stripe [2x160GB 7200rpm drives with DataBurst cache]
16X DVD+/-RW Drive
256MB ATI® Radeon® X1300 Pro PCI Express graphics card
Integrated Audio with Dolby Digital 7.1 capability
Dell 2 Button USB Scroll Optical Mouse - Black
Internal 13-in-1 Media Card Reader
Microsoft® Works 8 - English