Qbasic was supported on DOS-based platforms - what version of Windows did your previous machine run? You will need a new Basic environment that is compatible with 7. Or, if you are feeling silly and it ran under XP, you could run an XP virtual machine inside Win7. That's using a cannon to kill a fly.
This thread has suggestions: http://www.tomshardware.com/forum/4618-63-qbasic-windows