Hmmm.... there were some viruses that would "hide" a bit of memory, but I don't think it was 8 MB. Is Windows telling you there's 248, or the CMOS? I don't trust Windows to do that kind of math...
I'd open it up and take a look inside. What I'd be looking for is...
1. How many sticks of memory are in it, and how many memory slots are there?
2. What kind of memory is it (PC2100, PC2700, PC3100, etc.)? That's part of my shopping list, either for additional or replacement memory. Don't just buy whatever's out there; your motherboard may not work with it.
3. Hard drive is decent enough... for now [img]smile.gif[/img] 'Course, that depends on just how much of that 80GB you're already using...
4. Is it an AGP or PCI graphics card? An 8MB card would be pretty hard to find, even 18 months ago. A 32MB would be bare minimum, and 64 the most common. I'd upgrade to at least 128 if you can get it. Match the same type of graphics card, too. And since AGP comes in multiples (1x, 2x, 4x, and 8x), make sure that your new vid card can work in a multiple that your BIOS supports.
5. Processor is decent enough. Yeah, it's on the slow end (he says with an Athlon 2600+ installed), but it should do just fine. You might look at upgrades, but I wouldn't prioritize it highly.
You didn't mention the OS, but I would suspect XP or 98. 98 is limited to 512 MB of memory total; XP is not.