Sometimes your Sitecore solution may become unresponsive. This can be the result to A LOT of different factors. However, there is one circumstance that I just want to share because it is one of those stupid problems that no one should ever have to deal with. If you have performed the following actions your Sitecore site may become unresponsive event though it was working prior to these actions being performed.
Have you moved your Sitecore instance from one web server to another web server with a different machine key in the web.config?
Have you created two IIS websites and pointed them to the same folder on the file system?
If you have done one of these two actions above, your Sitecore solution may become unresponsive. Below is an easy solution or a tip to try under those circumstances.
If you have two IIS websites pointed to the same file system,in the world of Sitecore that is a "no,no". Sitecore will not function properly if two IIS websites are pointing the same file system path. Either copy the files to a different folder and point the second IIS website to the newly created folder or delete the other IIS site. Once that is taken care of then go to the “/Data” folder, find the “ViewState” folder and delete the entire folder. Don’t worry, it will get recreated again. You may have to perform an application pool recycle in order for the delete to take effect.