Do you have a wireless adapter?

(assuming win XP)

Check Control Panel > System >Hardware > Device Manager >Expand “Network Adapters”

If you have no wireless adapter, buy one. Probably PCMCIA for a laptop, maybe mini-PCI if your laptop has an empty mini-PCI slot- not all do, especially older ones.

If you have one, make sure it’s enabled (right click in device manager, properties)

Make sure the driver is installed / up to date.

Then either use windows zero configuration (Little monitor icon in the taskbar,) or whatever configuration utility came with the adapter to set it up to match your router’s security settings.

Edit - PCMCIA wireless adapters are cheap now… 802.11g is the standard you should be looking for, the most universal type… £10 / $20 USD would be a good deal.

PS - Bluetooth won’t allow you to connect to your wireless router and use the internet. Bluetooth is a different standard altogether.