Whenever a friend starts his laptop and starts Firefox (regularly updated to the latest version), it hangs for 8-10 minutes and the cooling fan noise increases noticeably. Also, the processor usage shows 80-90% while it hangs. This happens for the first time only. When he launches Firefox after that he does not face any issue even after hours of browsing.
OS: Windows 7, 64 bits
RAM: 4 GB
Processor : Intel Core i3, 2.26 GHz
He has habit of closing Firefox when multiple tabs are open and saves them before closing Firefox.
Temporary files deletion using CCLeaner and a virus scan is already done.
Windows 7 is genuine and regularly updated.
The problem occurs even when he starts Firefox 10 mins after he starts Windows. He had the same problem with Internet Explorer.
Is it because of some add on compatibility issue? Or bug in Firefox? Or too many startup processes?