Hitman 2: Silent Assassin doesn't exist according to this site.

It was "bought for free" at Square Enix Online Store using a coupon last month.

wow i was just checking the key and i beat the key ninja thanks

Widescreen Gaming Forum tends to be a huge asset in these kinds of situations. if they can't help you, chances are it isn't possible. If old games in highres is important to you, consider bookmarking it.

From link:

1. Run Hitman 2 at least once to generate the hitman2.ini file needed.
2. Go to the installation folder and edit hitman2.ini.
   (Note Danielsg: Open the file with any text editor, even regular notepad works)
3. Scroll down to 'resolution', and change it from 1024x768 (or whatever) to your desired widescreen res. (eg: 1680x1050).
4. Change the line 'window 0' to 'window 1'
5. Save your changes.

Edit: Seconding Sighery's recommendation of PCgaming wiki below, also a great tool in your fix-old-games toolbox!