Upgrading from 12.10 WUBI install to 13.04

Yes you can upgrade a Wubi install to 13.04, but Wubi support has been officially pulled by Ubuntu, therefore it's not recommended to do this.

Confusingly though, the 13.04 wubi.exe (signed by Canonical UK Ltd.) has been published on http://releases.ubuntu.com/13.04 (for undisclosed reasons). And no, the 13.04 wubi.exe doesn't only create a guest account. This bug was fixed.

If you do decide to upgrade which is generally not recommended on Wubi installs, then review this: Upgrading my Wubi 11.04 to 11.10 Also consider that you may not be able to get support from this site or other Ubuntu support sites.