It sounds as though the internal wireless card is out. Hate to say it, but that is not uncommon, particularly for certain models. You might want to check with HP's support site (if you have a computer that is on line), and check for bios updates/wireless card updates for your model...for some folks this does work, for others, no luck.
If you are out of warranty, you can consider replacing the wi-fi or if that is not easy/practical, you can opt for a plug in wireless adapter, be it USB, Express Card, PCMCIA card, whatever. Not the most "elegant" solution, but if you are not looking to spend much time or money, a reasonable fix.
I have an older Sony Vaio notebook where the built in wi-fi went "rougue", 4+ years old now, so rather than get deeply involved with it, I just bought a PCMCIA card and that does just fine.
Of course, if you are still under warranty, OR, if you have one of the models that was known to be "glitchy" and has an extended warranty, that is another matter altogether!