Hi Matthew,
OK the problem is moste likely to do with that you are running ASP.NET Version 2, where the web.config is probably setup/geared towards running on ASP.NET 4.

I hope this helps.

Anymore questions please let me know.
Warren :)

Ok. I'm a complete novice to ASP.NET and Umbraco. I normally work with PHP and a LAMP stack. Could you point me in the right direction of getting this fixed?

I recommend you install a new Umbraco clean instance using Microsoft's WebMatric tool. As when installing and setting up Umbraco, it will install any depenedcies needed like SQL Express and Update your ASP.NET version to 4 as well.

http://www.microsoft.com/web/gallery/umbraco.aspx

Once you have set this up, then you will probably have alot easier time setting up an already existing site.
Warren :)

Yeah. I've actually tried that as well already.

I have asp.net v4 installed and sql express. but when I try to use v4, I don't even get an error, just a blank screen that says it can't connect.

When you tried installing with WebMatrix. What problem/s did you have?

Well with the website you have setup, with the YSOD (Yellow Screen of Death error message) it shows that the particular site
you are running is using V2 of ASP.NET

In IIS maybe change the Application Pool that is linked to the site in IIS, to use V4 of ASP.NET instead.

I'm going to try the Webmatrix approach again. 

Using Webmatrix, how do I set up my site using the database that already exists from my existing site?

Hi Matt,
Like I mentioned before I would not recommend you setup your first Umbraco website with an existing database and instead rather start a fresh, to ensure your machine is all setup and configured to run & use Umbraco.

Once you know you can install Umbraco, then to run an Umbraco site that someone has already developed and sent you the files & datbase for.

It would be a matter of setting up a new site in IIS that points to the folder of files, with the correct permissions setup and modifying the web.config DB connection string to your own SQL DB connection string.

Any problems, just shout.

Ok. I've gone through everything. I installed a clean/working version in Webmatrix. It worked. Now I went through and tried installing my archived site and I have the error shown in the image. Any idea how to fix this?

It seems that the web.config of the archived site your trying to setup might have been setup in an ASP.NET 3.5 configuration.

http://our.umbraco.org/forum/getting-started/installing-umbraco/12945-Error-

http://our.umbraco.org/forum/getting-started/installing-umbraco/10095-Umbraco-45-Dontnetpanel-Server-Error-systemwebextensions?p=1

Cheers,
Warren

is working on a reply...