Nice perk of my current job is that we are allowed to spend time creating time saving programs. Within reason!
After getting an unusual number of reports of broken keyboards we decided we needed a quick easy way to test keyboards. Using mostly Apple iMacs, that is what we wrote the program for. BUT it works pretty good on windows as well (numerical keypad has issues though, but useable).
Spent less than a day creating the DIY Keyboard Tester using LiveCode.
Keyboard Tester Mac: diykeyboardtestermac
Keyboard Tester Windows: diykeyboardtesterwin-exe