The process cannot access the file because it is being used by another process. (Exception from HRESULT: 0x80070020)

 IIS Manager Error: The process cannot access the file because it is being used by another process. (Exception from HRESULT: 0x80070020)

The above is the exception comes most of the times when you are using the default web site in windows 7. Automatically it will stop the site and when we try to start then the above exception is coming. Because of it, no web sites, applications are running and unable to proceed to any further step. I know that the default web site uses the port number 80 by default. For testing purposes I have changed the port number to 9999 and tried to start the default web site and surprisingly it started and everything running fine. So, I fixed to the problem that the issue is only because of the port 80. I came to conclusion that someone else other than IIS web site is using the port 80.

Now, we found the problem. We need to look for solution. But, how to know who are using the port 80 other than IIS?

 Here is the post on it. "How to find what process is using which port?". The helped me a lot to find out the problem in minutes.

So, by following the steps in above post, found that the Skype is the culprit. Don't know why Skype needed the port 80. Actually there is no need to use port 80 by Skype. But, it's weird. Only Skype team can know about this.

So, finally to resolve this problem:

1. Open the task manager and kill skype process.
2. Go to IIS, and then start the default web site on port 80.
3. Do once IISRESET.

That's it. Everything should start working. Now, you can start Skype and use both. Enjoy.
Note: Make sure in this case it is Skype, tomorrow some other third party software. So, you should carefully read the post "How to find what process is using which port?" to resolve these kind of problems.
Hope you enjoyed it.