SharePoint 2010 subsite doesnt open

Hi,

We have 3 SharePoint Front ends server and I can access top level site and other site collections. But there is 1 SharePoint subsite that I cant access from central administration and also if any users tries to access the page it loads and loads without any result finally shows page cant be displayed.

Any reason why this is happening only to one subsite? The site was working from last 1 year all of sudden I have seen this problem. Any thoughts would be appreciated.

If I do IISreset page loads but after some time it goes to same problem. I am not sure where the problem lies and how can I trouble shoot this issue??