Are you still having issues?
I know it is frustrating. If you get an ethernet connection then you can narrow it down to the wireless side. The issue could be the way it connects to the router, radio interference, poorly written driver, or 3rd party drivers or software that breaks the driver.
Common issues are third party anti virus software and manufactures connection software.
if you PC is less then a year old Toshiba should be fixing on it. If they say its windows ask them which part and how is it that millions of PCs connect to the internet just fine and use windows 8.1