Installed Windows 8 developer preview and had hoped to get a dual boot setup, but no luck.
How can I move back to dual boot between my old Windows 7 and Windows 8? (Or perhaps revert to Windows 7?)
It's Windows 8 only, with a Windows.old directory. I do have a partition ready of course.
On the Windows Developer Preview downloads page it says
Notes about installing the Windows Developer Preview
You can't uninstall the Windows Developer Preview. To reinstall your previous operating system, you must have restore or installation media.
Refer similar questions
Should I install the Windows 8 Developer Preview on top of Windows 7?
How to revert to Windows 7 after installing Windows 8?
The WINDOWS.OLD folder contains all your Windows 7 files, it may contain data which you may want to keep, so back it up to an external drive.
Using this article from Microsoft support you can recover data from windows.old file. The summary for the article says
This article describes how to manually restore a previous Windows installation on the computer to replace the current Windows Vista installation. This article is intended for a beginning to intermediate computer user.
The article is intended for Windows Vista, but you can follow the steps and see if it still applies for reverting from Windows 8 Developer Preview to Windows 7 and then again try installing(dual booting) Windows 8 Developer Preview once you have successfully reverted back to Windows 7.
For dual boot refer these
Does Windows 8 Developer Preview 64bit allow multiboot when installing from a mounted ISO?
If you wanted to dual-boot, you'd have to manually create a 40+ GB partition (note: it has to be at least 40 GB, or you cannot install Windows 8) on your hard drive and use the bootable DVD to install to that partition, using the installer's "Custom" install path. By default it will load Windows 8 and then give you a nice GUI menu allowing you to select Windows 8 or your other OS(es). I have Windows 8 and 7 dual-booting. Selecting Windows 8 will immediately allow you to log in, while selecting Windows 7 will reboot the computer directly into Windows 7. Selecting Windows 7 as the default in that menu will give you your standard Windows bootloader menu the next time you reboot.
It sounds like you installed it as an upgrade to your existing Windows OS. You will have to reformat and reinstall to get it back (make sure you back up your files that you want to keep). The installer explicitly states that it cannot be uninstalled or installed side-by-side using the upgrade installer, so you're stuck with what you have unless you want to reinstall everything.
