Recently changed to a laptop set up and therefore find no use now for my iMac.
I have done a new clean install of OS X El Capitan 10.11.6
The ram has been updated to 4GB
The iMac "Core 2 Duo" 2.0 20-Inch (Aluminum) features a 2.0 GHz Intel "Core 2 Duo" processor (T7300), with two independent processor "cores" on a single silicon chip, a 4 MB shared level 2 cache, an 800 MHz system bus, a 250 GB (7200 RPM) Serial ATA hard drive, a vertically-mounted slot-loading DVD+R DL "SuperDrive", ATI Radeon HD 2400 XT graphics acceleration with 128 MB of GDDR3 memory, a built-in iSight video camera, and built-in stereo speakers underneath the 20" glossy TFT Active Matrix LCD (1680x1050 native) display designed to "bounce sound off the desk below".
Connectivity includes three USB 2.0 ports, a Firewire "400" port and a Firewire "800" port, built-in AirPort Extreme, and Gigabit Ethernet, as well as mini-DVI, which supports an external display in "extended desktop" mode.
Externally, the "Aluminum" iMac "Core 2 Duo" models feature "elegant" aluminum cases and have a glass cover that "joins precisely to the aluminum enclosure creating a virtually seamless front surface" -- compared to white plastic cases used by the models these replaced. Additionally, the "Aluminum" systems were paired with a "new ultra-thin aluminum" Apple Keyboard (0.33 inches at the front edge) based on the polarizing keyboard design introduced with the MacBook.