Yes, and I see my URLs didn't work very well for Andrew. (Andrew, you need to post your own thread, exactly as you do here.)
Therefore, um, what's left? I think I'll leave it to you Brits, because I'm not sure that solutions here apply there. In Windows, in North America, there are 2 platforms now. People without money, or who are techs with special purposes, use tweaked old Windows 98version2 systems. You need to be either poor or skilled to do that. When XP was introduced in late 2000, it changed everything, so it became pretty well synonymous with "Windows." Of course, there are a few ME users; and there are also certainly a lot of businesses still using Windows 2000, which remains a very decent program.
Therefore, a person here would tend to have XP, unless there was a reason to have 98v2. Apple remains popular with educators, although it is now third to Linux, which appears to have passed Apple going in the other direction!
Of course, XP was always fastest of the Windows OSs, and you can visit benchmarks on the net to see the comparisons. ME was almost useless on limited power, and crashed terribly, unless the system were upgraded. (I loved my ME, but I enjoy working with computers. Mine was silky smooth at the end, and very fast; I hated to let it go.) In NA, few systems have been slower than 1.2 GHz for a few years. Mine is a ho-hum 1.7, and would rate competent but ordinary.
RAM and hard drives are extremely cheap--virtually giveaways. Neither are considered an upgrade here. But Diane is right: you wouldn't mess around with a motherboard and things like that unless you were in that 98 category, setting up an old machine, maybe on Linux, to do some special task--or unless you were right into playing around with computers. You would pretty much have either one system or the other.
You don't hear about "sweet spots" anymore, although what appears above is, or was, true. ME takes 512 as easy as pie, though, so when costs dropped through the floor, the very few ME users remaining didn't hesitate to use 512. This is all in NA, and I'm just mentioning it for interest. And, as two people suggested [above], there is a point where the RAM is too much for the machine, and works against it. (That isn't the "sweet spot", which is the point of OPTIMUM efficiency, after which more RAM is still advantageous, but less efficient.)
CD-ROM manufacturers were not necessarily nice about changes in systems. Some were good business people, and made their drives adaptable. Others had the audacity to suggest you "upgrade," i.e. buy a brand new CD-ROM from them. That angered many consumers into buying their new CD-ROMs from competitors. However (again, as mentioned above) that kind of problem could certainly not be addressed with RAM. RAM is immediately-available memory that lets a computer do lots of things at once, or remember heaps of information; or perform tasks nice and fast. But it won't help if the hardware is simply incompatible.
No matter what hardware you have installed, it does require the computer to acknowledge its presence, whether or not you are using it at the time. On old 98v2 systems, you could not simply load things on board for a free ride. Well, you could six years ago; not for a long time now. That's why, now, these systems are generally dedicated to specific tasks. Of course, one such specific task is saving money a person doesn't have.
A brand new computer, monitor, and printer--the whole system, complete with ADSL--costs around Canadian $1500 now. In the States, it might be $1000, but that's US dollars. Basic systems are advertised from $300, but I'm talking about an honest-to-goodness finished product, all taxes paid, sitting and humming along on your desk.
The same amount of money would buy a pretty bad old beat-up car. Or, as pointed out above, it would buy one return air ticket to pretty well anywhere.
That's all just for conversation. I guess, Andrew, you have to take the ride that we all do. You can easily own a computer, but there is a lot to learning about it. You don't need to obsess with it, but I do urge you to make it fun. Like anything else, it's a lot easier to enjoy when you like what you're doing.
All those forums are friendly, but maybe I was wrong anyway; perhaps they're not for you. In reverse, I HAVE mentioned BIRDS in COMPUTER forums from time to time. Does that strike anyone as odd? Well, then, you get my drift.
I generally come to bird forums to talk about birds--and I go to computer forums to talk about computers. You do have a big audience of people watching the questions and answers in any forum, so, if the subject is their special interest, they tend to keep you pretty safe from anything but pretty good advice. That was my point.
And I don't mean any of this as advice, because I still think this is not the best place to get advice. As I said before, the people who know their stuff can glance through here and SEE the good advice--but they don't need to ask the question; it's easy for them, because they have that advantage.
I also apologize if I appear to have talked down to anyone, which was certainly not my intention. There are lots of very intelligent computer operators at ALL levels. Actually, all of this is an endless theme in the Firefox Browser forums. Firefox is a superb browser, but is it for beginners? The more people know, the harder it is for them to remember what was difficult at first. So, lots of techs advocate Firefox for just anyone. Others are more cautious. [Firefox replaces Internet Explorer, or can just be added to any system. Fx is nifty-keeners as a really NICE research tool, but you begin with basics and get to know it gradually.]
Good luck, and good birding!