The easiest way is to attach the drive to a working machine which has a CD drive, then fdisk and format it, and copy/paste all the contents into a 'folder' (hate that word! It's a directory!!).

Before you do it, though, make sure 'view hidden files' is enabled.

An external drive unit is very handy for this sort of job.

PSU checker? I use a multimeter!

It's easy enough to make a PSU checker with a few LEDs and resistors, and a power socket from an old main board... an LED will only light if the polarity is correct and the resistors will limit the voltage so a 12v line won't light the LED if there's only 11v present. You can use trim pots instead of resistors if you want real accuracy! But why bother if a multimeter tells you everything?

The P4 plug depends upon the age and type of the PSU - different manufacturers put different labels on - these days it tends to be a square 12v auxiliary (two yellow and two black wires), but it could really be anything!!

There's a lot of crap spoken about PSUs - a 90w unit may be able to provide that continuously (RMS), yet a '400w' unit may only be rated 'Peak Power', which could mean as little as 75w RMS in reality. It's not unlike amplifiers and loudspeakers, really.

If the PSU feels heavy, it's possibly better (but not always!) than one that feels lighter. The PSU is usually the component that fails, and often takes something else out with it. I was asked to look at a dead PC not long ago... someone had spilled coffee in the PSU, and the whole PC was scrap. No, not quite true... the CPU fan was okay!

There are too many things that can go wrong on a main board, and it's rarely worth the effort to find out why, particularly as you'll never be able to trust it again...!

Hopefully the memory will be okay. It's never a good idea to mix types, even if the board should support it.