Hmm, re-installed everything, but when I went to install the LAN device I noticed that it hung on the DOS window and didn't do anything, restarted, re-installed and it all seemed fine.
However, then the computer started taking between two minutes and forever to boot up properly (the three scrolling blue bars below the XP logo), programs were crashing, and it was completely freezing up for a few seconds every so often, all things that it wasn't doing before I format it!
I wasn't sure if it was related to one of the CD drives again because they were doing funny things, and sure enough on the final boot up it couldn't find the (rather temperamental) DVD drive and it seemed to run fine.
Is this purely coincidence do you think? Or is it the genuine cause and should I just completely disconnect the DVD drive? I know I should have checked it more but it's getting late now so thought I'd just check on here and get back to it tomorrow. Thanks!