I have just bought a Tosh. and am about 90% certain they have a FAQ about this sort of problem on the uk support site, spotted it while I was checking before installing a Dell mini-pci wirless card in the laptop (One bit of Tosh. said it would void my warranty to do it myself, the sales team said it was a self install...it's now in and working!)
Ok here you go:
1st a Toshiba WiFi trouble shooting guide:
http://www.csd.toshiba.com/cgi-bin/t...sp?soid=509572
Might be worth a quick read but looks like you have tried most of it HOWEVER...
The Toshiba UK site is down at the time of this edit...
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edited to add links.
edited re Toshiba site status.