DOSBox
DOSBox is an emulator that recreates a MS-DOS compatible environment (complete with Sound, Input, Graphics and even basic networking).
DOSBox emulates an Intel x86 PC, complete with sound, graphics, mouse, joystick, modem, etc., necessary for running many old MS-DOS games that simply cannot be run on modern PCs and operating systems. This emulator lets you run many classic MS-DOS games completely unmodified. In order to utilize all of DOSBox's features you need to first understand some basic concepts about the MS-DOS environment.
Excellent free alternative to Windows, also very suitable as modern operating system on older PCs (DVD iso).
Ultimate Boot CD 5.3.9 assembles over 100 PC hardware diagnosis tools into one bootable CD to analyze and repair hard drives and to fix boot problems (CD iso).
WinRAR is a powerful archive manager that is compatible with many compression formats. It is commercial software, but you can use it for free.
Provides ongoing improvements to the Windows Operating System (OS), includes previous updates delivered over Windows Update as well as continuing incremental updates to the Windows 7 platform (DVD iso)
If you need to create bootable USB installation media from ISOs like Windows or Linux, Rufus can create these in a very easy way. Just select the ISO file and simply point to the USB drive, that's it!
Windows 11 UX Pack transforms your Windows system 10 into Windows 11 with themes, wallpapers, and sound effects.
Hiren’s BootCD PE contains many tools you can use for analyzing, recovering and fixing your computer, even if the primary operating system can not be booted (CD iso).