最近新装了IE8，调试ASP.NET时发现，设置的断点被视而不见。google了一下解决方法：
一、关掉所有的IE窗口再调试。
二、摘自http://social.microsoft.com/Forums/en-US/vsdebug/thread/e2c795cd-b7a0-4fad-b7c9-b1ca40d7302e的
Older versions of the Visual Studio Debugger get confused by this and cannot figure out how to attach to the correct process. You can work around this by disabling the process growth feature of LCIE. Here’s how:

1) Open RegEdit
2) Browse to HKEY_LOCALMACHINE -> SOFTWARE -> Microsoft -> Internet Explorer -> Main
3) Add a dword under this key called TabProcGrowth
4) Set TabProcGrowth to 0
Since you are running on Windows Server 2003, this is all you should need to do. If you run into the same problem on Vista or newer, you will also need to turn off protected mode.