First of all, my thanks to lwcomputing for your insight. I have and use a lot of the tools you listed already, yet there were a number of ones I am glad to add to my arsenal. My main reason for wanting to buy a commercial kit is that I see a lot of dead PSU's (we live near a lightning "alley"). So when I replace the dead PSU and it still doesn't start, is the motherboard dead, the cpu, or both? Did it also fry the video card?
And then there are the laptops. One mystery notebook I own, starts and runs anywhere from 1 second to 30 minutes, then shuts off. I know water was spilled down that one by the first owner. (I took it in on trade). I have disassembled, examined, and cleaned this one completely several times. So now which proprietary component do I start buying to swap out until I choose the right one?
electronicsfreak pointed me to UBCD (one of my regularly used live CD's) and also to a post card at Newegg. The commercial kits include post cards, and some of them also include a PC Card post card for notebooks. I definitely want one for notebooks as well as one for desktops. The PCI post card would be useful to me, but I want to buy an all-inclusive kit instead of parting it out over time.
I do have lots of hard drive enclosures (firewire, USB, 2.5", 3.5", SATA ...) and a USB 2.0 to IDE/SATA adapter that fits 2.5", 3.5", and even 5.25" drives. I have a digital multimeter, a coax and RJ25 cable tester (yes, I need an RJ45 tester -- but not enough to buy it yet), and an Antec PSU 20 pin loader (I need a 24 pin loader now, and I think I'll buy an Antec again). I do have a USB floppy drive, and lots of spare 3.5" internal drives (too bad notebooks aren't so accomodating since so many don't boot off USB floppy). I have lots of Live CD's, from various flavors of Bart's PE I've made, to UBCD, System Rescue CD, PTDD, Kanotix, Knoppix, GRML, MemTest 86+, all the HDD manufacturer's diagnostics CD's, Acronis Migrate Easy, GParted, and even a forensics Live CD (although I don't need it).
Here's another interesting notebook (a customer's): it starts to boot then hangs -- until you pick it up and hold it a certain way. Then it boots. I thought hard drive at first, but it passed those diagnostics (SMART, quick and extended). But it does the same thing booting off a live CD. Once it boots up, it runs without any further issues, for as long as you like. So is this a motherboard issue, a grounding issue, or what? What component only comes into play at boot, and then no longer matters? Honestly, I don't know.
Anyway, I work alone, so I can't bounce ideas off other techs at work, and if I'm stumped I would like a resource like a commercial diagnostics kit to turn to. Since it's a fair amount of money, I want to get the right one the first time, and that's why I'm asking for advice.
And I definitely appreciate the help. Thank you again, Chuck.