HP Pavilion G4-2002tx Networking :: Not Connected - No Connections Are Available

Product Name: HP Pavilion g4-2002tx Notebook PC
Operating System : Microsoft Windows 7 ( 64-bit)
 
My wireless internet connection has been working fine until recently when the connection with my home's internet modem became intermittent .  There will either be a computer icon with a red cross icon shown which states " Not connected. No connections are available" or the fully filled white bars with a yellow warning sign icon which indicates "Limited Internet Access", thus I could not connect to the Internet anymore.
 
I believe that the fault does not lie in the modem because the other devices in my home such as smartphones or other laptops were able to connect well with the modem when the problem which the laptop encounters has occured.
 
I have tried restarting the laptop repeatedly or even perform a System Restore until there is Internet Access ,however I can only have access to the internet for a short while (not more than an hour) before the above mentioned problem occurs again and the whole vicious cycle continues.
 
For now, the internet connection seems to be working fine again , however I do not know when the wireless connection will go haywire again.