Microsoft will end extended support for XP SP3 on April 8, 2014. If you are connected to the Internet, best of luck keeping the bad guys out of your computer after that date.
Are you sure you can't get the printer to work under Win7? What's the model number?
Whoops, I should have read more of the thread. There is a Win7 driver for the OKI C3200. Sometimes it helps to temporarily shut off your anti-virus program, clear all your temporary files with a program such as CCleaner, reboot, then run the printer installation routine as administrator. If installation fails, run eventvwr.msc to find what specific errors occurred.
Even better, create a new installation with Service Pack 3 slipstreamed in.
Here's a link to a free program that automates the process of making customized Windows XP installation disks.
http://www.nliteos.com/index.html