Reset the IP eh? Should we assume this is for a network connection?
In order for the Scan to Computer feature to work there needs to be a client installed and working on the computer to recieve the scan jobs. Not sure what the OJ 8600 uses for your OS but that is most likely the best place to start looking. Many times HP has an application like HP Toolbox or Solution Center that is constantly running on a computer. If that app is not able to recieve a scan job then there is nothing for the printer to send its scans to.
Check your installation logs and see if there is any mention of an error during the scan setup. You can also try running the HP Scan and Print doctor posted here: http://h30499.www3.hp.com/t5/Multifunction-and-All-in-One/Trouble-printing-or-Scanning-Try-the-HP-Print-and-Scan-Doctor/td-p/5809027
Otherwise you may have to resort to a pull scan 3rd party application on the computer as opposed to the push scan to computer feature from the control panel of the printer. Some free examples would be MS paint, MS Word or MS Scanner and Fax wizard.