Microsoft likes to talk big about backwards compatibility in Windows. Those Windows apps you bought for the previous version of Windows, they'll say, will work fine in the current version of Windows. Programs you buy for this version of Windows should be ok for the next version of Windows.
The problem is: when does backwards compatibility become a hindrance, rather than an advantage? At some point, isn't it just better to move on, and put the past behind you?
Not for Microsoft. They work hard to maintain that backwards compatibility. IMO, this will one day be their downfall.
Take, for example, the discovery of a 17-year old Windows bug, which Microsoft is only now addressing in February. Reported to Microsoft in June 2009, the bug is in code that supports old, legacy 16-bit applications. The effect: an attacker can run any code on your system. The exploit has been verified on XP, Vista, Windows 7, Server 2003/2008.
I'll go easy on Microsoft about their response in releasing a patch .. this time. 7 months (June 2009 to February 2010) is probably an appropriate amount of time to unwind a bug that's been in the operating system for 17 years. Probably.