Can you enable logging and look what's there? Is it for just a default.apsx or any requests to the site? Did you upgrade to different IIS version as well?

check if you have access for the iis user to you files and folders. vs should not do anything specific regarding the project. Also se if you can compile the project, the version of .net so that you have the same in iis as you have in projectfile. you could also try to run aspnet reg iis command for the version you ar running. 

If you are using IIS Express the above should not be needed. Then you should check the logfiles as Vladis told you. Enable log in episerverlog.config in the root of your website. You could also check the windows log and applcation under computer management.

It's for all requests, all return 404.

VS2008 uses Cassini and VS2013 uses IIS Express. Could that be the cause?

How do I enable logging in erpiserverlog.config?

Could not find anything in the Windows log.

Yes that might be the issue...since cassini if i remember correctly has a web.config that is more like a web.config for iis 6 and express use one for iis7. So you could try to install an empty episerver site and copy that web.config to your folder.

The log you can enable logging via the config file: http://world.episerver.com/Documentation/Items/Tech-Notes/EPiServer-CMS-6/EPiServer-CMS-60/Logging/

Set the warnlevel and also the path were you should store the file.

As far as the episerverlog.config it seems to be enabled but no files are being written.

I assume there should be a reference to the config file from web.config? I can't find one.

You can check whether user has permissions to write to directory you configured in logging config file. I would suggest to set logging event to 'All' - just in case. Is file appender uncommented in 'root' section in log config file? Try to host site in IIS (just create new site pointing to directory where web project is, config app pool in integrated mode).

Which .Net Framework you are targeting?

Nothing wrong with permissions.

File appender looks okay in config file.

Hosting a new site with the same directory results in the same error.

Targeting .NET 3.5.

Check your log4net version. Should use 1.2.10. So if you host your site in IIS with the same config file, IIS does not complain about any incompatibilities in web.config file? Is your app pool set to "Integrated"?

Couldn't find log4net in the project so I got the nuget, version 1.2.11.

No, no complains about incompatible web.config file. Not sure where I'd see that complaint though?

App pool is set to Integrated, yes.

Adding new files to the root and trying to request them doesn't work so I'm guessing it's a server issue?

Maybe going from VS2008 to VS2013 is far too big of a leap?

It shouldn't be tooo huge leap otherwise there would not be such a progress :)

If you just copy files (.html?) to IIS direcotry and try to request those resulting in error sounds like really some a server problem.

If EPiServer is consuming 1.2.11 lognet version - log files may not be created (known issue). Downgrade to 1.2.10.

If IIS complains about some compatibility issues in config files - that should be directly in on screen when accessing the site.

Another stupid Q: is app pool and site even started in IIS?

Hey, I'm the one with the stupid Qs. :)

Yes the app pool and site is started. Trying with IIS or IIS Express (through VS debugging) both yield the same result.

Could it be a missing handler or something?

i would copy a web.config from a standard installation to your root of that site. If you have an old web.config it might not start with iis7 or express. just make a standars installation of en empty episerversite and then copy that config.

Taking another web.config file causes all kinds of other problems.

Sounds like this is not purely EPiServer issue :) Can you share some of the problems you face?

If you get other errors changing config at least you have contact with the folder for the site. All kind of errors can be caused by you not having the same sitespecific settings in that web.config file.

As Vladis said, it would be great if you could share some errors.

I think it's saying I'm missing a handler for the file type?

Detailed Error Information:

Not sure, maybe this could help.

http://serverfault.com/questions/427475/http-500-internal-server-error-on-iis-7-5-with-mvc3

I've been looking at this http://world.episerver.com/Documentation/Items/Tech-Notes/EPiServer-CMS-5/EPiServer-CMS-5-R2/Changes-Between-IIS6-and-IIS7/

And tried it but still no luck. I call it quits now. It's not worth more of anyones time. :)