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.
qbasic is not well-supported natively on Windows newer than XP SP3 32 bit (I've gotten, at least on Vista/7/8 32 bit, qbasic to run so long as I didn't try full-screen mode, which would always crash) according to my experience with them. I'd suggest using XP mode (if available to you) or using a virtual machine if you want better QBasic compatibility. WyomingKnott has good suggestions and a good link.
Chief beat me to it - you can run a lot of stuff in Dos Box, assuming that you really want to. I only use it for some of the great old games, and since the XML5 version of Lemmings came out why bother?