Okay, this question might be a little obvious, but I'll ask anyway.

My roommate's got an older computer, with no PS2 port for the mouse (and I assume an AT port for the keyboard). Anyway, he had an old one that was really crappy attached via the serial port. It was a PS2 mouse but he had a serial port adapter.

So he just bought an optical mouse, and it's a USB one, but it comes with a PS2 adapter. You see where I'm going, I'm sure

So with all the adapters attached, his computer doesn't recognize it. It's an old P100, so it's pretty ancient by today's standards. Is there anything he can do to use his new mouse?

Have his computer up-to-date with his mouse

I'd say get at add-on USB card, but seeing how it is a P100, he is probably not running 98SE.

LOL.... You're right of course. He'll probably spend as much getting the new mouse working with his old PC as he would if he went and bought a new low-end clone.

Yeah, thanks guys, that's what I figured. He might as well get that Walmart PC that rob told us about. I might just suggest that to him...

He actually is running 98, but I'm not sure if it's SE.

PS/2 to Serial and USP to PS/2 adaptors for mice are specificially made for that model mouse, and nothing else. Essentially the mouse can support either, and will run the right signal down the cable depending on what it detects. There is no actual smart component in the adaptor it's self, thus the adaptors cannot be combined.

Look up the motherboard. Being a Pentium class board, I bet it has a PS/2 port, it's just going to need a cable with a PS/2 connector to be plugged into the header on the board. To easially verify this, check the BIOS for any PS/2 options, or check the Device Manager for a PS/2 port (it usually uses IRQ 12).

Remember, eBay is your friend. There are tons of decent computers that will go for well under $200. For a full system with a not-so-bad chip, it's a great deal.