What are cabinet files?

Cabinet files are a lot like zip files. They contain other files in a compressed format.

Whether or not you can delete them depends on what they were for, which typically depends on what software you've installed.

There are a couple of ways of dealing with them.

Many programs are now distributed using cabinet files to contain the actual files that comprise the application. Very much like
zip files, cabinet files use a compressed format to place multiple files in a single container.

Cabinet files are typically used to distribute software. When you install a program, the setup program extracts the necessary
files from the cabinet files and copies them to wherever they are supposed to go on your hard disk. Normally cabinet files
reside on a CD or other distribution media, though occasionally the setup program will copy them to your hard disk. If so, the
setup program then either leaves the cabinet files behind, or deletes these files when setup is complete.

Occasionally, as a kind of optimization for later, the setup program will leave the cabinet files on the hard disk so that later, when you might need to run setup again, you don't need to provide the installation CD.

Ultimately whether or not you can delete the cabinet files depends on the expectations of that setup program. The safest thing
to do is to first back up those cabinet files by copying them somewhere else - either onto a CD or another computer - then delete them and see what happens. If it turns out that the cabinet files were necessary, you can then simply restore them from wherever they have been copied.

Most of the time you can safely delete cabinet files that you no longer need, but I'd be sure to back them up first anyway.

Ultimately, though, if you're not sure, and they're not actually causing you a problem, the safest thing to do is to leave them be.