I found out how to uninstall the IE10 preview and I have done so because of the cookie handling issues. I was reverted back to IE9 exactly the way it was before installing the preview, fully updated and running the 32 bit version. My verdict on IE10 for Win7 is, "Not ready for prime time".
To uninstall the preview, type Programs and Features into the search box and then click on the same words in the displayed list. Then click on view installed updates at the left, scroll down to Windows Internet Explorer 10 under the Microsoft Windows header, and uninstall it. You will revert back to what you had installed previously.
Now that I'm back on IE9, I can say that the speed increase in IE10 is minimal at best. You have to use the 32 bit version of IE9 to get it's fastest possible speeds. Now I have to reinstall speckie though to get spell checking back. I had removed it. All other addons and settings reverted back to how they were before however.