After purchasing the Toshiba Qosmio laptop, I have seen that only 450GB of 500 are available. Few hours after purchase I discovered that two large hidden partitions were created by Toshiba. One is 1GB large and it seems to be the standard Windows 7 hidden partition - but obviously much larger. The second one is not less than 10.3GB in size! It seems to contain the recovery software (Windows setup, drivers, etc.)
The second partition is safe to delete since the so called "recovery" tool offered by Toshiba is 100% useless because it will format your drive and reinstall Windows instead of actually trying to recover the data for you.
So, no matter what you do, DO NOT use Toshiba's recovery utility if you have and important files on your drive!
The partitions can bee seen using the Disk Management utility.
Start>Control Panel>Administrative Tools>Computer Managment>Disk Management
Just delete the last partition (not also the first one!) and expand the previous one to fill the free space.