TFS 2010 RC, getting 404 on http://localhost:8080/tfs

I just installed tfs 2010 rc basic on my win 2008 server. Everything went ok with no warnings but when Iad try to access the team web access I get this error in a yellow box on the web page

TF31002: Unable to connect to this Team Foundation Server: servername:8080/tfs. Team Foundation Server Url: servername:8080/tfs. Possible reasons for failure include: – The name, port number, or protocol for the Team Foundation Server is incorrect. – The Team Foundation Server is offline. – The password has expired or is incorrect. Technical information (for administrator): The request failed with HTTP status 404: Not Found.

EDIT:
A default collection was installed by default and is called DefaultCollection.
If I go to http://servername:8080/tfs/DefaultCollection/ i get a blank response (no error). The TFS admin console claims the collection is online, but if I try to edit group membership or administer security I get an error msg "Team Foundation servers unavailable" Http code 404: Not found

I tried reinstall, uninstall and reinstall but no luck and even nothing in the event log. Very frustrating.
Does anybody have some advice for where I should start looking?

SECOND EDIT:
The server is a 32 bit win server 2008 SP2, the Team foundation site is running on a .net 4.0 application pool classic. I had tfs2010 beta 2 installed before which also did not work because of a bug causing tfs believe the server was on a domain which it is not. The beta 2 installation was uninstalled before installing RC. The site is not bound to a specific ip address but is on port 8080 all unassigned. There is also ca 10 other websites running on this IIS setup with http headers and bound to the servers ip address

THIRD EDIT:
Reinstalled, made sure site at 8080 was removed, made sure no Sharepoint, WSS but still same problem
Full size

FOURTH EDIT:
Both application pools was set to use LOCAL SERVICE, The http://localhost:8080/tfs/web seems to work from what you can see from the screenshot. I changed the identity of the Microsoft Team Foundation Server Application Pool to use my local administrator account but still no luck. I also changed the account in the TFS admin console to use my local admin account but still the same error. It seems strange a security error would throw 404 as well. Checked the logs and no errors beside my trying to access the http://localhost:8080/tfs/ site