Ok I have an old lappy 400mhz 160mb ram? (163,000kb) 6.5 gig drive what am i gonna install on it

Not a whole lot, really. You could run something with a very lightweight WM, like Fluxbox (maybe XFCE) but GNOME and KDE are more or less out of the question.

I would suggest something like Slackware, Arch, or pure Debian for the distribution. These distros will let you easily strip out a lot of the unnecessary services and packages to eek a little more performance out of the machine.

What do you want to do with it?

How bout running without DE?

+1 for using Debian!

6.5 GB hard drive doesn't leave much breathing room. How about Puppy?

Generally any regular distro will be too big for this old of a laptop, a very streamlined slackware install could work, but slackware doesn't stop you from removing things you need so be careful. I can't speak for debian really.
Damn small linux is somewhat dated and the project has halted but it's still very good for hardware like this as it's a good balance of full-featured and lightweight. Puppy could work too, it would be easier and more up to date than damn small. you could also use tiny/microcore and build up from a very tiny core system, making sure you have what you need without all the extra that comes with most distros.

Something to look out for though, some minimal distros [notably, puppy] will default to a single user mode so for a hard drive install you should probably change to runlevel 3 or 4 (can be done by editing the /etc/inittab) to allow multiple users and force a login. Better for security issues, and helps if people other than you will be using this laptop.

I would opt for Slackware, Debian or Arch, minimal install, then build it up from ground. If Arch is not possible (may be because the CPU doesn't support i686) ConnochaetOS may be a good choice instead. I still fail to see why running a distro that loads to RAM (like Puppy or Tinycore) would be a good choice on a system with only a small amount of RAM.

Building an installation from a minimal install is a bit tiresome. There are several distros that will run in 160MB, and the easy ones are AntiX, ConnochaetOS, and Vector Light. AntiX is the lightest: it recommends 128MB (but can get by in 64!), 266MHz, and 2.2GB of HD for the system, so you'd do fine. It's very stable distro; in fact, it's just an installation disk for Mepis.

Not worth it. Recycle center and then Craigslist/Freecycle for something with a little more "oomph."

Even KMandla, the patron saint of obscure text-based distros on ancient laptops, finally got rid of everything older than Intel Core Duo...

With X11: puppy Linux
You ought to look what could be well maintained.
A Debian Stable for low configuration would be great, but it however does not exist (not possible)

Without X11, for console only: Debian Stable

Lol thks snowpine I know. It has now become an obsesion to get it to run I,m looking at Antix (DavidMcCann) at the moment, And where to get a stripped down debain iso

Back when I had a 500mhz Pentium 3 with 128mb ram, I had an OK result with the "loram" flavor of SliTaz. AntiX is great too.

Honestly it's not the distro you have to watch out for so much as memory-hungry applications. For example as I type this, Firefox alone is using 140mb ram, and that's not even very heavy browsing. Therefore it's not so much a question of "how do I install Linux on this thing?" but "what do I actually do with it now?"

Funny how we take a challenge on from windows users

That's not old. I installed a Debian netinst on an IBM Thinkpad 233mhz with 96mb of memory and a 10gb hard drive. It may have been 6 years or so ago. I put fluxbox on it for the environment.

It ran pretty decent. In fact, I still have it around here someplace but haven't used it in years. I may dig it out and see what's up with it.

Another one to consider: Tiny Core Linux.