Old PCs and Laptops

The typical specs:
Video card 2MB
CD drive

V.90 Modem

USB

Two PCMCIA slots

64 MB RAM

4 GB Hard Drive

Intel Celeron 400 MHz

It's currently running Windows 2000 Pro.

You can't (or shouldn't) run XP. Or even 2000. 64 MB is the minimum
requirement for both systems, and you're going to be seriously hampered
by a lot of swapping with either. You could try installing XP Lite,
but even so... running something like Firefox is absolutely a no-no. If
you could throw another 64 MB in there you'd be in better shape, but in
reality for any modern operating system 256 MB is the bare minimum you
should be using.
Windows Fundamentals for Legacy PCs, which is so cool that Microsoft doesn't sell it to customers Windows FLP still requires 64MB RAM minimum. It really doesn't decrease the
memory footprint all that much. You get hosed up as soon as you want to
run more than one application at a time.I feel like I'm beating a dead horse here, but WinFLP, Win2K, and WinXP
all have the exact same memory and processor requirements, both minimum
and recommended. WinFLP, quite frankly, only reduces the hard disk
footprint. It's really not a good OS recommendation for what he has.
None of the above will run half decent with 64 MB of memory, I
guarantee it.

Xubuntu would fly on it. I ran it on an old 233 mHz G3 iMac and was very impressed with responsiveness.
Even the default Xubuntu install won't work without more RAM. There is
an alternate install you can use, and Xubuntu will run on 64 MB once
installed, but you'd really need at least 128 MB.
Fluxbuntu is quite nice, and would run on that.




I have run both DamnSmallLinux and VectorLinux on a laptop with half that much memory

Dell Latitude D233ST laptop

Mobile Intel Pentium II microprocessor 233 MHz

4.3 G hard drive

64-MB RAM

64 MB is going to hurt, but if you use XFCE4 instead of Gnome, it should be okay.
Ubuntu can run XFCE and Fluxbox, too.
Damn Small Linux is built for modest specifications.
Try VECTOR LINUX. it's a slackware based distro built especially for machines with less resources http://www.vectorlinux.com/

oh, 233. Well I run debian with fluxbox on a 200mhz box. It's impressive...but not modern.

Linux distros for older hardware