When I go to check out a system. First I remove the mobo from the case, install the cpu again "just to make sure everything is done right". Then I install a stick of memory, a video card and hook this up to a powersupply and a monitor I keep for this type of stuff. Then I hook up a hard drive w/OS already installed on it. Floppy drive I have already with a ribbon cable, all needed is to hook to a power connector and plug in the ribbon cable. These are the items I use to diagnose a problem.

1. Powersupply w/good amps on 12v & 5v rails
2. Working lightweight monitor & canned air
3. Hard Drive w/80 pin cable already attached OS installed
4. Floppy with 40pin cable already attached
5. Supply of Shin Etsu thermal paste for installing cpu
6. Supply of memory sticks & anti static strap
7. Supply of screws various sizes etc
8. Variety of screw drivers-Needle nose plyers,OmMeter,cold sorder etc.
9. Black Boot Disk w/repair utilities and diagnostic utilities etc
10.Virus detection disk & Program to find and remove all spyware

I have a 17" monitor that is very light in weight and works with every system I have found. The powersupply is a new 350Watt that I did not sell so I use it for diagnostics etc. The tool kit is not extremely large so It can be taken from one place to another when necessary.