D-Day for Windows 7 RC approaches
If you're still running Windows 7 RC, starting March 1st your PC will shut down automatically every 2 hours. Your work will not be saved. But you can still use the OS, as long as you're willing to put up with periodic interruptions and reboots. It'll be kind of like using Windows 98 all over again.
Come June 1st, the OS fully expires. That doesn't mean it will stop running altogether. But in addition to the automatic shutdown every 2 hours, your desktop background will change to solid black and you'll have a message on the desktop letting you know the RC has expired. Windows 7 RC will also fail any Windows Genuine Advantage tests at that point, meaning you won't be able to validate software that requires a "genuine" copy of Windows and you won't be able to get Windows 7 updates from Microsoft.
You can avoid these issues by replacing Windows 7 RC with another operating system. We'll leave it up to you to decide whether that means Windows XP, a fully licensed copy of Windows 7, or something else altogether. ReactOS, anyone?
Update: Looking to figure out how to upgrade from Windows 7 RC to a full version of Windows 7? We've got you covered.