WampServer

Hi all,
I have been using wampserver(64bits) on my windows 7 since last one and half year and never came across such a cumbersome situation. What i am frustrating at is about suddenly getting a 404 error while trying to connect with localhost.

I didn't updated any software nor i did OS update or didn't do any application installation before i get this error. Now i explain you:
I start wamp from start menu, an orange-then-green wamp icon appears on the taskbar, near the clock as it happens in normal case. But when i type localhost it throws me error saying:
" HTTP Error 404. The requested resource is not found." i checked my firwall, hosts file and wamp setting, uninstalled, and then freshly downloaded and installed again but same thing happening.
Please anyone if knows solution, share the knowledge.
Thank you all,

I just downloaded and install WampServer and get the same error.