Hello Tofy Yoo,
Installing all of the software using the Toshiba recovery discs should have put back a proper Toshiba licensed copy of Windows onto the Toshiba.
Please download and run the Genuine Diagnostics tool at this link
http://go.microsoft.com/fwlink/?linkid=52012. Click "Run" several times to download and start the Utility. When asked, click the "Continue" button. When the utility completes its run, click the "Copy" button, then come back here and paste the
report into your post.
Also, please look on the computer for a Certificate of Authenticity (CoA). If there is a CoA, please tell us what version and edition of Windows is listed on the CoA, and if there is a manufacturer's name or "OEM Software" or "OEM Product" printed
on the CoA. Do not post the product key printed on the CoA.
Or might you be referring to needing a product key for the Office Trial that might have been put back onto the computer by the recovery discs?