Windows product key

I bought a toshiba satelite C660 laptop, which came with microsoft windows operating system already loaded. I was able to restore my laptop to factory settings when I was having problems. However my hard drive on my laptop failed, and I had to have a new hard drive installed, the repairer put windows 7 home on it. The product key label was on the base of my laptop and over the years has become unreadable, is there anyway I would be able to recover my licence number from microsoft and maybe the toshiba restore function, so I would be able to restore to factory settings?
TIA

 

I no longer have the original hard drive

 

Purchased from Argos in June 2012 and no longer hold the receipt, dont have the toshiba restore option on a disk, however my daughter has an idential laptop, purchased from same retailer, on the same day and she doesnt have any problems with her laptop, would this be any help to me?

 

Ive emailed toshiba, so will wait and see what they suggest,

 

Here's another option.

http://winaero.com/download.php?view.1781

 

I dont have the original hard drive anymore, it failed.

 

In all honesty, Toshiba may tell you that you need to purchase a Product Key. I got a retail key for Win 8.1 Pro from ebay for $60US. I had no problems activating Windows with it.

 

If you want the Product Key of the Windows on your new Hard Drive, do what I suggested. But, if you don't have the original disc, it's worthless.