BobsYourUncle wrote:
If all else fails,
Reboot everything.
This is good advice but if you only choose to reboot one thing, reboot your router. It seems counter-intuitive that the router needs to be rebooted since other devices connect fine but it often fixes these types of issues.
If rebooting the router doesn't help then you should delete the connection to the router and then re-create it.
If those 2 things don't get you going again then I would get a USB dongle, they are inexpensive and work surprisingly well. Since you say this is an older, seldom used Toshiba I imagine you wouldn't want to spend a lot of money so here's one that works well and will cost you less than $10:
Ultra-Mini USB Wireless Lan 802.11N Adapter