You couldn't have gone from Vista 32-bit to 7 64-bit. You can only go from 32 to 32 or 64 to 64 through an upgrade. But anyways, what you're supposed to do is:
1. Click the Start button, click Control Panel, click Programs, click Programs and Features and then click Turn Windows features on or off.
2. If you're prompted for an administrator password or confirmation, type the password or provide confirmation.
3. Select the Games check box and then click OK.
That being said, you should really have performed a clean installation. All of your old Windows Vista files are located in C:\windows.old. Most people, including myself, recommend that you perform a clean installation rather than upgrade, since upgrading leads to a lot of problems. If you have an Upgrade disc, here's how to perform a clean installation using it: Clean Install Windows 7 With Upgrade Media and Product Key on Formatted or Empty Blank Hard Drive My Digital Life