xp sp2 + aspnet_regiis caused HTTP 500 Internal server error

I'm trying to install .net framework (from microsoft downloads site) on xp sp 2. IIS was installed after installing the sp2. After installation, I got the 'the page cannot be displayed' 'HTTP 500 internal server error message', even on http://localhost.

Going around in the sp2 docs lead me to the IIS Lockdown Tool 2.1. Running the IIS Lockdown Tool 2.1 (link below) twice (first to lock, second to unlock) removes the lockdown, and HTML pages work. aspx, however, will still not work.

When I run the aspnet_regiis.exe or reinstall the framework, I was back to square one - the same error repeats itself.

It seems that I'm going around in a loop. I could not find any reference on the problem, though.

I'm currently going around in a loop - unlocking the IIS means I have to run aspnet_regiis again, but that locks the IIS again. Does anyone have the solution?

Links:
http://www.microsoft.com/technet/prodtechnol/winxppro/maintain/sp2otech.mspx#EAAA
http://www.microsoft.com/downloads/details.aspx?FamilyID=dde9efc0-bb30-47eb-9a61-fd755d23cdec&DisplayLang=en

I would run the lockdown tool to get to the unlock state, and then get everything going with IIS, then re-do the lockdown tool. I'm not real up on the lockdown tool myself.