I highly doubt it`s a hardware problem. Having owned a few HP laptops and experienced the exact same problem you`re describing, it could be that the wireless adapter somehow became disabled within Vista.
Go to the Control Panel, double-click on Network and Sharing Center and then in the left-hand column, click on Manage Network Connections. Right-click on the Wireless Network Connection icon and click Enable. If it`s already enabled you could try clicking Repair instead... or click Disable and then click Enable again.