If you jumped onto Microsoft Windows 7 pre-release version (Beta or RC) you can't upgrade to the final RTM version and need to do an clean install loosing all your settings and installed application as Windows 7 setup won't let you upgrade from a pre-release version to final build displaying error as below.

Luckily there is a simple config-file hack which allows you to do an in-place upgrade from Windows 7 pre-release to final version keeping your files, settings and applications intact.

Microsoft Windows 7 Beta 1 which got leaked and cracked a few days ago, is being reported to corrupt some MP3 files when used via included Windows Media Player 12, users on forums are reporting data corruption issues because of this bug in Windows 7 beta 1 build 7000 while playing MP3 files using Windows Media Player 12, Approximately 2-3 seconds data will get cut-off from the beginning of MP3s as Windows Media Player 12 tries to retrieve meta-information from internet and write it to any MP3 file with a Meta data header larger than 16KB.