Necessary Software for Your IT Toolbox

1. Disk Cloning Solution:  I'm partial to Acronis Backup v11's Live CD for this job - it's fast, easy, and well supported.  However, we can't always have the luxury of a $90 backup solution.  For those customers without an Acronis license I use G4L - Ghost 4 Linux - it's an intimidating looking tool, and it's certainly not very fast, but the price can't be beat.  Learn how to use G4L at http://www.oakdome.com/lab/?page_id=8.
2. Password Reset Solution:  My fave tool is chntpw.  Available as part of the excellent Kali Linux computer forensics toolbox, chntpw allows you to edit the registry offline (and I can think of reasons to do this far beyond password reset).  If you don't want to fuss with an entire Linux distro just for chntpw you can use the excellent Offline Windows Password & Registry Editor - this is a LiveCD or Bootable USB that will make NT passwords as easy as Linux can make them.  It is chntpw neatly packaged in a LiveCD, so it also allows registry editing.  Be certain to read the fine manual because the interface looks quite intimidating.
3. Windows 10 Upgrade DVD:  Many businesses are making the switch to Windows 10 because it is more secure.  Viruses and spyware are hounding users.  Windows 10 has several improvements that help prevent viruses.  It's also faster, more stable, and has some neat cloud management features.  Follow these directions  to get some Windows 10 iso goodness and create your own Upgrade DVD.  If you're upgrading I suggest booting the target computer into Windows 7 then running the DVD, booting from the DVD is for clean installs.  Windows 10 installs using the computer's Windows 7, 8, or 8.1 license key.
4. RAM Diagnostic CD:  BSOD, slow boot, disk corruption, slow shutdown, poor performance, hangs and freezes, all can call for a RAM diagnostic.  Memtest86+ has been my go-to for quite a while.  Download the latest version, unpack it, and burn your iso to a CD.  Run it with all of the RAM installed and allow it to do a few passes, if it finds nothing, shut it down and call it good.  If it shows errors or freezes then shut down and pull out all but the 1st stick of RAM.  Boot into the diagnostic and allow a few passes - if it passes 4 or 5 times, shut it down and repeat with the remaining sticks until the faulty one is identified.