Try the deinstall steps at http://docs.oracle.com/cd/E17781_01/install.112/e18803/toc.htm#CIHDDHJD
And ... note as it says in the documentation for installer requirements, there is no listing for any Windows X64 OS. If you want to try the x64 XE version, best try it on linux.
With a boot .ISO and virtual box you can have a linux host up and running, and XE install+configured in 30 minutes, or less, if you're comfortable with unix. If not ... might take a bit longer.
See https://virtualbox.org its much easier to use than some of those (very pricey, other) vm programs available. Getting the clipboard copy/paste to work between your VM and desktop is a bit of a challenge, but not having that work is not a serious setback, by any means.