I promised I would report back on what happened, and so I am here a week or so later, and currently still using Linux.
My previous post was probably while I was feeling the 'honeymoon' period with Linux. I went on to have a go installing from the CD, and probably stupidly, tried to install it into the last 4 GB of my ailing hard drive. This seemed to go to plan until I rebooted the computer and discovered that neither linux, nor windows was going to load again! I probably should have read instructions in more detail. Anyway, it had transpired the CD I was using was somehow corrupted, so I burnt a new CD on my gf's laptop (very slowly), and decided to wipe the laptop clean. This time it rebooted beautifully, ubuntu appeared, and everything looked rosy. I was happy again!
Everything, as before, worked. At the moment I largely use the computer for the internet - buying, gmail, maps, ebay, news etc etc. No problems with firefox, although I must admit that I slightly miss google chrome. Open office works without any problems whatsoever, in some ways better than my copy of microsoft office 2007, which bizarrely decided to rearrange all the buttons from the previous version. Again, things ran smoothly.
That was, until I tried to print! I won't go into the several hours it took to find, convert and install the printer drivers for my iP2500 canon printer. I only really persisted because I refused to be beaten. The outdated drivers came from the canon website, required converting into debian format, which required a terrifying foray into 'terminal' - the text-based doing-thing. I honestly didn't know what I was doing, and for all my competence could have been rewriting the operating system. Once I had the packages installed, I still had problems, as apparently the driver pointed to outdated libraries, and again I had to use terminal to work out which ones it was trying to get to, which ones I had, and then to redirect the driver to the correct one. At the end of ~4 hours of sweating and googling, I got the printer to print a test page, and it has worked a charm since then.
The other problem was the music, which would cut out everytime I switched screens, closed screens, minimised to desktop, or pretty much do anything. The problem seems to have somehow slowly resolved itself without me doing anything, and then I cut out the graphical eye-candy from the preferences which seems to have prevented it from happening again.
So after 1 week, a quick review:
PROS
Works beautifully without problems, once it's working. Seems perfectly reliable. Boots very quickly. Does not meddle with your hardrive while its running. Very convenient controls on top right of screen which give you access to the music player, your calendar, and your email. Connects quickly and without fuss to networks. Excellent reliable internet usage.
CONS
Does require some technical knowledge. Installing some stuff requires figuring it out. Either just works or just doesn't. By default has some fancy graphics tricks that can floor an old computer. No google chrome (yet). Have had a couple of niggles with some websites vs firefox.
Overall, I'm very happy with the system. Haven't yet tried any photo-editing.
Thanks for the help nanok. I will definetely be writing to you when I get stuck!
Duncan.