Will I be able to upgrade WIndows 8 Release Preview to RTM without losing programs?

Q: Will I be able to upgrade from pre-release versions of Windows 8 to the final release?

No.

For those of you who have already been running the Windows 8 Developer Preview or Consumer Preview, you can install the Windows 8 Release Preview using the migrate option (just keep personal files), but not the upgrade option (keep personal files, apps, and settings). Or if you prefer, you can of course do a clean installation (keep nothing). The Consumer Preview release does permit upgrading from Windows 7, and will run the integrated upgrade advisor to check on any things you might need to look into. Please keep in mind that there is no rollback after an upgrade installation. We also strongly recommend that you perform a system backup prior to an upgrade, migrate, or clean install of Windows 8 Consumer Preview.

Also note that the final release of Windows 8 will not support upgrading from any prior Windows 8 "Preview" release, though the migrate option will still be supported. In any upgrade scenario, you can run the Disk Cleanup Wizard to remove the previous installation in order to free up disk space. The download will also support boot from USB for a completely clean installation as well.

Microsoft do not recommend upgrading from a beta, and may actively prevent it.

Windows RTM should always be clean installed which means preferred applications and utilities have to be clean installed too.

As stable and as polished as recent betas have been, there can sometimes be quite dramatic code changes in the background which would royally screw up upgrade attempts, leaving the user with an 'anything but polished' installation.

Note also that Microsoft do NOT recommend the use of betas in a production environment, regardless of how good they seem to be. If you have placed all your eggs in a beta basket, prepare to see some broken.

One of the broken eggs is the inability to uninstall Windows 8 and revert to the previous OS, and another is that the ability of the computer to be able to access its own recovery partition may be removed, leaving the user having to pay for manufacturer recovery disks.(all according to MSDN).