And the specs of that computer would not support Win 7... not enough memory or enough processor. Also, if you COULD load it it would run very poorly because the driver support for the hardware is not there.
That machine was probably meant to run Win 98 or some such, and will never work with a modern OS.
As Proximon said that rig will never be able to run Windows 7 even if you could get it to install a Intel Celeron 500 MHz would be so slow that you would never be happy with the performance or lack there of. On top of that the max memory looks to be 128meg witch is not enough to even really boot Windows 7 let alone run any app. Time for a complete upgrade.