p.s. ive tried to wipe the cache and factory reset wipe too.
Go here... Stock I897UCKK4 Android 2.3.5 One Clicks *Heimdall and Odin*
If u want to use the Heimdall version that I linked, then use the same USB port that u used to flash the other heimdall one click that u mentioned.
If u want to use the Odin version, then use a different USB port, Because the heimdall usb drivers are installed only to the one specific usb port that u r using at the time of the install. That is more than likely why the computer is not recognizing ur phone when u r trying to use odin.
Here is another thread that may help as well... Captivate - PC Connection Issues, Download Mode and Recovery Mode Help