Motherboards and Batteries?

[Maxipak]

The problem is this, a few weeks ago my desktop PC broke down, for the third time in a month, which I soon had to replace due to my college course being IT related. I now have a new computer that has similar specifications to the preceding one which seems to be running pretty sweet so far, knock on wood.

Now I've taken on the task of repairing my old PC as a hobby of sorts, I know it's probably a lost cause, and I've now had an idea after remembering a conversation I had with my older brother a year or so back concerning motherboards, specifically I found it amusing that motherboards use/used batteries.

To the point, the old PC is suffering from a blue screen that occurs every time it passes the XP loading bar, just before the user log in menu. Now, seeing as the PC is about 3 to 4 years old now and I used to leave it running for days and weeks non-stop, I'm wondering if the motherboard's battery might be the culprit of my grief.

Here's a few specific questions I have:

1. Do motherboards use, or did they use, batteries?
2. Does the battery power the BIOS and when?
3. What does the battery actually do? - Just to satisfy my curiosity
4. Could the battery, in any way, cause my computer to receive a blue screen?
5. Is it possible to change the battery?

PS: Due to the inconvenience, I'm not actually up to plugging the machine in to check on anything at the moment, but I will be within the next week or two.
Thanks for any info or replies.

Edit: I haven't updated my computer specifications within my user profile, so it might prove useful while deciphering the problem.

[The New Normal]

I think the mobo battery is just there to keep the CMOS memory. This is where the BIOS is stored; removing it clears the CMOS and resets the BIOS, which can be useful in some situations.
The battery is round, about the size of an oversized coin. Funnily enough I just realised I've got one sitting on top of my puta. It's a Duracell 2032 3V with 'Medical' written on the case. Bit of a coincidence that, lol.

I don't think that's your problem, as you're clearly getting past the BIOS stage.

Blue screen with a memory address on it? Typically a hard-drive or RAM issue, but sheesh it's hard to tell with these things, could be a corrupt windoze.

If it were me, I'd start by taking out all RAM sticks except 1 (of course you may only have 1). If there were no joy there, and I didn't have any data I needed to save I'd pop in the XP setup disk, re-format and re-install Windoze.

Let us know how you get on.

[Maxipak]

It is possible that it may be my RAM or operating system, but the hard-drive is still fresh from Bigpockets so I don't think that's the problem. I was planning on setting up the machine sometime today so I suppose I could try that RAM trick, but I'm not too optimistic abut it; when my computer broke down for the second and third time, I attempted switching, removing, and resetting the RAM, leaving at least one in of course, but every time it wiped out.

Fate must've gotten a killermanjaro for the amount of times that machine crashed on me.

It did eventually start but it only recognized one stick of RAM, the 256mb one, and later recognized both due to a Windows update; the machine is using a 256 and a 512 RAM combination.

If I do get it running again I was thinking of installing Ubuntu on it, unless you want to recommend any other versions of Linux; I'm looking for the Linux equivalent of Windows XP Home Edition.