Under References folder. See if you have System.Data.Entity. (you should) It should be v4.0.30319

If you don't, add the reference.
C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0\ System.Data.Entity.dll

Okay. This is making some more sense now. Here is what I have found...

I checked my System.Data.Entity reference but it is actually at 3.5.0.0. It's located at

C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.5\System.Data.En tity.dll.

So I tried to navigate to the directory you mentioned but I only have 3.0 and 3.5!!

Which led me to believe that I had a bad install. I went ahead and reinstalled and also used a .net setup verification tool found here...

http://cid-27e6a35d1a492af7.skydrive.live.com/self.aspx/Blog|_Tools/netfx|_setupverifier|_new.zip

and everything checks out!

So I went ahead and checked out the directory that I mentioned I had seen before made me think I had 4.0 to see if I could find that .dll, which is...

C:\WINDOWS\Microsoft.NET\Framework\v4.0.30319

one exists and when hovered over with the cursor, gives me the version number of 4.030319. I added this one as a reference to see what would happened and there is a yellow exclamation point which appears next to the reference in VS. When I check the properties, it gives version 0.0.0. The compiler also gives lots more errors.

So what can I do to get a valid 4.0 directory with all the files I need (System.Data.Entity.dll) in my C:\Program Files\Reference Assemblies\Microsoft\Framework folder???

Thanks again.

I wonder if older dll is stuck in cache. Google for "gacutil"

I've located the gacutil.exe for VS 2008.

C:\Program Files\Microsoft SDKs\Windows\v6.0A\bin

What exactly do I with it??

Sorry trying to type with phone. From command prompt type

Gacutil /cdl

Then try to build again

OK. It ran the GAC Utility which is under 3.5 it looks like.

It says the Download cache was deleted successfully. Rebuilt my solution and nothing happens.

Is there something else I need to do?

So nothing meaning that there is no improvement? And errors still there when compiling?

Oh, sorry.

Yes. Still the same error.

Check the Target framework of the project.

Right click on the project
select properties
select Application tab
Look at Target framework. What version do you see?

It's under 3.5.

4.0 is not even an available option in the drop down list!