If you have IE 8 installed and your ASP.Net project won’t stop on the breakpoints you’ve set they you probably need to read this article
You basically need to add an entry to your registry to stop process growth for tabs.
I’ve copied the steps required below
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