Kind of a newbie and maybe even stupid question but before I get my hopes up too high (which I'm probably already doing because I haven't worked with real wireless security yet and I'm not sure it'll work as well as if I can do everything good enough in linux to be compatible with windows)

Anyway this is what I need and what I think now:

Pentium III or celeron at least 1GHz - No problems here I'd say
RAM 256 MB - again no trouble
hard disk - Is it sort of the same as IDE drives in desktops? Expect no problem here
Monitor - will work anyway isn't it?
sound card - Trying to get an alsa compatible
graphic card - I'm worrying a bit here. A lot of laptops I saw have ati cards. Do they work good enough now in linux? Or is it still better trying to find nvidia ones? (Just compatibility, I'm checking benchmarks out later but they're made in windows so they don't say really much)

DVD reader/cdburner - haven't heard of this combo yet but might be just DVDburner/cdplayer as well. Am I right in expecting no problems?

Lan networkcard and modem - no trouble here?

Are there any things I should be checking that could cause trouble with linux?

Thanks for the help!

You really need to google around for 'name/model no. of laptop + linux' to see what people say about it. Many laptops include proprietary hardware that manufacturers refuse to release drivers for so some laptops will not work well in Linux.

So there could even be problems with things like burners, harddisks etc.? Or is it just the normal things, like video cards , wireless card, networkcard/modem?

Come to think of it does linux have support for (some of) those touchpad mouses?

It would be more the wireless card. But what I meant was that the motherboard can be too proprietary for Linux to even run on it. I'd say that disks and CD drives would generally be ok - they'd just be like normal drives in a desktop.

Anyway the point is you should check the make and model of your laptop to see if other people have success running Linux on it.

I see. Cause I'm not so sure the laptop will have a name or so. I know which wireless works and which not so that's ok.

Thanks for the warning about the motherboard though I wouldn't have thought of that.

I have an IBM ThinkPad R51 which is a little higher specced than your requirements but one of the things I learned while installing Slackware on it and getting stuff working was that Debian and IBM laptops seem to get along quite well.

I think that for slightly older IBMs with the specs you mention you'd probably have a fairly easy time getting everything working.

Centrino looks pretty good for me now as it's supposed to give pretty long battery life and it's supported completely. Still a bit unsure if I want a real video card though, might play some old games better.

Thanks for the help!

download knoppix, take it around to the current laptops owner before you buy the laptop, see if you can boot... tada :-) you know if it works!
i sofar only met one single laptop that was not able to boot with knoppix, but i am sure it is still possible to get linux to run on it.
mobo, hdd, cdrw should not be a to bigger issue,
sound cards can be a little tricky, and graphics... well, dont expect to have the linux 3d support :-) (meaning - nono playing gameses)

Well I doubt the shop will let me run it

I've played around with soundcards a lot and it looks like intel is supported quite well. I actually didn't expect to play games on it. I've thought about nvidia or ATI card but maybe it's better to go with intergrated card and not bother. I probably need winXP a lot more anyway cause of uni so I might as well play a game in there. And I still have my desktop which runs any game I have so far and I doubt I'll buy more games soon anyway. Maybe if I upgrade my desktop as I read laptop is 30% slower with similar hardware and that if you want to game you have to think of buying a new laptop every year.

Cause with the extra card come questions like shared ram or not, more CPU etc. which isn't very good for battery life which I'll need definitely.