Yes, Bluestacks will work on Windows 7 as long as the requirements listed on the official websites are met: https://bluestacks.zendesk.com/hc/en-us/articles/201691647-Windows-8-1-8-7-installation-requirements-
- You must be an Administrator on your PC.
- Your PC must have 2GB of RAM/main memory. (Note that having 2GB or more disk space is not a substitute for RAM)
- Your PC must have 4GB of disk space available for storing Android apps/games and their data.
- The drivers for your PC's graphics drivers should be updated for compatibility with BlueStacks as described in the following post
It's highly recommended that you have a capable GPU card to enjoy full graphic processing power.
Here's an alternative if you can't work with Bluestacks: http://www.memuplay.com/