Note this machine is not supported by Toshiba for win7 (too old) but I proved it can be done!
If this system does not work right, not sure anything was proven. Vista, W7 and W8 share the same driver database, but not all drivers universally support all 3 operating systems.
That said, this Toshiba driver page
indicates Toshiba does support W7 (32 and 64-bit) on the U300 (select "Archive" for the Product type).