Asp.net site could not load file or assembly

I know that it is a common problem but I really have tried all the solutions and nothing helped me so far. I am developing a .net site for more than two month... Yesterday I have faced with this error:

'Could not load file or assembly 'myDllName' or one of its dependencies. The process cannot access the file because it is being used by another process. (Exception from HRESULT: 0x80070020)'.

And I can't find any solution for this. Anyone has an idea??

I have already:

1. close the VS and re-opening.
2. reset the computer.
3. clean the project and the solution (from the vs)
4. clean manually all the bin folders of the project.
5. clean asp.net temporary files(including 64 and 86 version).
6. change the compatibility of the default application pool in the IIS manager to 86.

In this case, I would open a blank solution and slowly add the DLLs that you care about to get the smallest version of this problem possible.

In my case, when I encountered this error, the key part of the error message was "or one of its dependencies." One of my DLLs was dependent on another DLL I didn't know about or I would have included it.