Laptop stopped detecting wireless singal

I have a Conpaq Presario F500 laptop I'm using windows vista operating system.
Since January 2008 I have succesfully connected to the home PC router via wireless network. One day last week it was connected the next day i could not pick up any signals.
The other laptops in the house pick it up as usual, just mine has stopped.
It would usually detect up to 3 signals from neighbours routers and now it shows none. when i troupleshoot it says that "this computer does not have wireless network adapater installed and configured".
The physical device is on as the amber light is on.
In control panel I cannot open the icon that says 'HP wireless assistant' so maybe somethings gone wrong with that?
I have followed windows help and support and downloaded updates but it has not seemed to help.
What else can i do?