Hey Arulprabu89. This is probably not the case, but I just have to ask - do you have any type of screen lock or password set? Because if you do, it will recognize the phone, but until you open unlock it - you won't be able to access it from your computer. At least this is how it is with my Nexus 7, it's a security measure. On the other hand, try reinstalling the drivers.
Here's another type of solution which might be of help.
1. Enable USB debugging: Go to phone settings -> About -> Tap build number repeatedly until developer menu is enabled. Go there and tick USB debugging.
2. On your PC, go to your device manager (when the Phone is plugged in and set to MTP), locate the phone, right click on it -> properties
3. go to the Driver tab
4...