If you're going to be relying on your server to any extent, you'll want to make sure it doesn't collapse out or give up suddenly, and this is where this step comes in. Some may be tempted to skip it, and to be honest if you know your system is completely fine then you're probably OK skipping this step. However, I'd personally still recommend it.
Though please bear in mind, whatever testing you're using, this is an OLD system, please make sure your data is backed up elsewhere - just in case!
First of all, have a mini vacuum cleaner and a can of compressed air handy. Then open the case and (gently) get rid of as much dust and gunk as possible. When you've done this, unplug the various cables, blow the dust away from there and then reseat them (in their original positions!) It's good practice to clean any PC like this regularly, and with something that hasn't been used in a while it's good to give it a fresh start!
Right, next on to testing the system.
I'd recommend StressLinux
for this, it's a livecd distribution that's designed to run a series of tests on hardware, and includes memtest. Now if you're in the same situation as me you'd now be thinking something like "I'm stuck with a computer that's completely incapable of booting from CD!" However, all is not lost, we simply need a bit of extra help, and this is where Smart Boot Manager
comes in. It's a neat little utility that boots from a floppy, then gives you options to boot from everywhere on your system it can.
Follow the link above to download stresslinux, then burn the ISO image to a CD, being careful to create a disk from the ISO image and not simply copy the ISO file onto a CD - that won't do anything useful. If you need it, download and install smart boot manager to a floppy. Set your BIOS to boot from the relevant medium, and stresslinux should fire up.
To start with, I'd test the memory. Type in "memtest" (no quotes) into the boot: prompt and press enter. Leave it to it's own devices for a good few hours - the longer the better. You should have no more than a couple of errors at most, preferably 0, after this time. If the number of errors is high or rising significantly, you most likely have a problem that will prevent you using anything with more than a minimal degree of reliability, if at all. Look into this before you progress further.
After memtest has run for a few hours and assuming there are few or no errors, reboot your system and boot back into stresslinux, this time just hit enter when greeted with boot:, and follow it's steps through to set it up. When it's running, run badblocks on your hard drive and CD-ROM drive, you should have, again, no more than a couple of bad blocks on each, if that.
To run badblocks, simply type badblocks followed by the drive, which will probably be:
/dev/hda for the primary master
/dev/hdb for the primary slave
/dev/hdc for the secondary master
/dev/hdd for the secondary slave.
The most likely configuration is that the hard drive is on /dev/hda and the CD-ROM is /dev/hdc. So to run badblocks for the hard drive:
and for the CD-ROM:
Be patient and wait for it to complete. Assuming no problems, you're now ready to start the Gentoo installation procedure.