You are sure a Dell user!
And you are certainly not alone:
http://www.5starsupport.com/xp-faq/1-67.htm
http://help.lockergnome.com/windows/Show-window-contents-dragging-problem-ftopict7815.html
http://www.pcreview.co.uk/forums/thread-319387.php
http://forums.us.dell.com/supportforums/board/message?board.id=sw_winxp&message.id=104214
http://www.tomshardware.co.uk/forum/25218-35-show-window-contents-dragging-work
http://www.tech-archive.net/Archive/WinXP/microsoft.public.windowsxp.basics/2004-02/0411.html
Possible Workarounds:
- Uninstall Dell Media Experience
(seems to be cause for the most of the links above, but I handn't installed it) - Use MSCONFIG to disable the services of your video and audio drivers.
(this solved it in my case on a Dell XPS M1330 64-bit) - Add this small tool to your autostart programs
HTH!