Hello saandeepa,
Welcome to the HP Forums!
I understand your touchpad is freezing on your HP Pavilion 15 Notebook.
Let's start by making sure the drivers are up to date. You can find them here: Synaptics TouchPad Driver.
Also take a look at this document for touchpad issues in Windows 8: Using and Troubleshooting the TouchPad or ClickPad (Windows 8).
Let me know if this helps at all. 