What do you see in My Computer? If it's not there, look at disk management. If you have Windows 8, you can get there by right-clicking in the bottom left corner and selecting "disk management" from the menu. If it's Win 7, right-click Computer in start menu and click Manage, then go to Disk Management.
If you restarted with the drive in, it won't pop up though. Open My Computer and check there first.