In the future this is what your downloads folder is for. It should contain all of your app and program installers and be backed up along with your other data.
There is no program worth trying that will reinstall your programs, however if you are happy with your Windows 7 and it's the same version you can try to apply an image after
SysPrep to move HD to another computer.
There is also a freeware CD that was widely available several years back that is harder to find now called Paragon Adaptive Restore which can be booted to adjust the old installation to the new hardware.
PAR is also a part of Paragon's recent Backup imaging program, and is comparable to Acronis Universal Restore which are two programs that will adjust a saved image to new hardware when reimaged to it.
Sometimes the old Windows 7 HD or image will start up on new hardware, as well. But don't count on it.
Nothing is better than a
Clean Reinstall including a new computer since most of them are larded with corrupting bloatware and useless factory utilities which have better versions built into Windows 7. At the minimum I'd
Clean Up Factory Bloatware before installing your programs.