The Dell Outlet is your friend. This machine is already Vista ready and for the price is an amazing machine. It's in the scratch-n-dent section but has a full warranty so who cares if the case ain't perfect??? Hard drive is a bit small but you can always add another.
$369.00 OptiPlex GX620 Pentium 4 - 2800 Genuine Windows XP Pro 80 GB EIDE SATA Hard Drive (7200 RPM) 1000 DVD-ROM 128MB Radeon X600 Desktop
Here's the specs
OptiPlex GX620
(System Identifier: EZ00RGH3)
OptiPlex GX620 Desktop: Intel Pentium 4 Processor 521 with HT (2.8GHz, 1M, 800MHz FSB)
Genuine Windows XP Pro
System Price : $369.00
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Operating System
Genuine Windows XP Pro
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Memory
1 GB DDR2 NON-ECC SDRAM 533MHz (2 DIMMs)
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Hard Disk Drive
80 GB EIDE SATA Hard Drive (7200 RPM)
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Video
128MB Radeon X600
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Scratch & Dent
Scratch & Dent
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Base
OptiPlex GX620 Desktop: Intel Pentium 4 Processor 521 with HT (2.8GHz, 1M, 800MHz FSB)
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Media Bay
16x DVD +/- RW w/dbl layer write capability
Software
Power DVD Software
DVD Software
Power DVD Software
AOL ISP Software
Operating System Software CD
DVD Software
AOL 9.0 ISP Software
Software
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Misc
System Documentation
Dell Enhanced Multimedia USB Keyboard
No Floppy Drive Filler Panel
Labels
No Resource CD
AOL Software Documentation
RoHS Compliant Lead Free Chassis and Motherboard
USB 2 Button Mouse
XD DISABLE BIT WXPSP2 SET TO O
Shipping Material