Buy.com offers the refurbished Lenovo ThinkCentre M55e Intel Core 2 Duo 1.8GHz Desktop PC (no monitor), model no. 9637-Q2U, for $199.99 with free shipping. That's the least expensive Core 2 Duo-equipped ThinkCentre desktop we've seen with Windows XP Pro. It features an Intel Core 2 Duo E4300 1.8GHz dual-core processor, 1GB RAM, 80GB 7200 rpm hard drive, DVD/CD-RW combo drive, Gigabit Ethernet, and Windows XP Professional.
Buy.com - Lenovo ThinkCentre M55e 9637-Q2U Mini Tower Desktop, Intel® Core 2 Duo Processor E4300, 1GB, 80GB, DVD/CD-RW Combo, Windows XP Professional
Refrb Lenovo ThinkCentre Core 2 Duo 1.8GHz 1GB, 80GB, DVD/CD-RW $200+free ship 
