ISS can lock the ASP.net Temp folder files
Problem:
If you're browsing to an asp.net page and your browser reports "Sever Error in '/' Application." and "The current identity... ASPNET does not have write access to 'c:Windows\microsoft.net\framework\v2.0.50727\Temporary ASP.net files', you might naturally think of adjusting NTFS permissions for the ASPNet account or running aspnet_regiis -ga in the attempt to correct the problem.
Possible solution:
Try stopping any and every service that has anything to do with either Blackice and/or ISS (that's ISS, not IIS). Particulary look for the "ISS Buffer Overflow Exploit Prevention" service. Stop it. Restart IIS. Test asp.net functionality.
The application event log may have an event resembling this logged:
Event Type: Warning
Event Source: ASP.NET 2.0.50727.0
Event Category: Web Event
Event ID: 1309
Event code: 3005
Event message: An unhandled exception has occurred.
Event ID: 0746e871023341b099dd3393e82e464d
Application domain: /LM/W3SVC/1/Root/Blahblahblah
Process name: aspnet_wp.exe
Account name: COMPUTERNAME\ASPNET
Exception information:
Exception type: HttpException
Exception message: The current identity (Computername\ASPNET) does not have write access to 'c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files'.
Request information:
Stack trace: at System.Web.HttpRuntime.SetUpCodegenDirectory(CompilationSection compilationSection)
at System.Web.HttpRuntime.HostingInit(HostingEnvironmentFlags hostingFlags)