What speed prosser and memory are needed to run Ubuntu

- Minimum system requirements to install Ubuntu 8.10 https://help.ubuntu.com/community/Installation/SystemRequirements

Hope this helps

I guess you mean that your laptop has a processor with a clock at 450MHz and 256MB of memory.

You can run Ubuntu on it, it is fine :-)
Perhaps, you could also try Xubuntu (http://www.xubuntu.org/), which might run faster on such hardware. Basically it is the same as Ubuntu, but it uses less memory and can run slightly faster on an older processor.

Make sure you turn off any graphical features, like translucency, fading effects etc.
Xubuntu is the same underlying operating system - i.e. you can run the same programs - but uses a different graphical interface, that's less polished and maybe a bit less user friendly and less "automatic" than gnome (with Ubuntu) or KDE (with Kubuntu).
I used Ubuntu on a 1200MHz, 512MB laptop, and that was fine (even some animations worked pretty well), and I know someone who uses it on something even slower (he upgraded to 256+64 MB memory, cos his 128 MB was always filled). However, to be honest your system sounds really like pushing it to the bottom. If you want thinkgs run smoothly, maybe ask around your friends whether someone has an old 256MB or 512MB stick that's compatible to prop it up a bit (some applications like open office can really soak memory) or go for the Xubuntu.

If Xubuntu doesn't work, there are even smaller versions of Linux operating systems that are meant for bare bones machines. DSL comes to mind:

http://damnsmalllinux.org/

Other small linux distros might be better. DSL isn't so small ad it's a bit quirky i think. I prefer Wolvix, or sliTaz or AntiX or even Puppy if i must but DSL was a bit disappointing to say the least

http://distrowatch.com/table.php?distribution=wolvix
http://distrowatch.com/table.php?distribution=slitaz
http://distrowatch.com/table.php?distribution=antix
http://distrowatch.com/table.php?distribution=puppy
http://distrowatch.com/table.php?distribution=dsl
http://distrowatch.com/table.php?distribution=xubuntu

DistroWatch is a popular place for comparing different different versions of linux (different distros) as each of the pages is given a standardised look so it's easier to compare them. If you navigate to their homepage from any of the above then you see that Ubuntu is clearly far ahead of even it's nearest rivals. Being most popular in DistroWatch isn't always the best indication of how good the distro is but in Ubuntu's case i think it's well-earned :)

Good luck and regards from
Tom:)

Have you tried Xubuntu? most of these can be just run from the Cd you make without installing anything to your machine. Pick one you like and see how it goes with installing it. I always find it better to go with the type of dual-boot described here although the OS's might be Win98 and Wolvix rather than Xp and Ubuntu

https://help.ubuntu.com/community/WindowsDualBoot

Good luck and regards from
Tom :)

If you are still having trouble with this then please post it as a new question. Only the most recent questions tend to get looked at so posting/reposting a question just before america arrives online after work/school gives the best chance of getting a good few answers.
https://answers.launchpad.net/ubuntu/+addquestion

If the problem has been resolved then please follow the link to the forum thread and mark it as Solved.

Good luck and many regards from
Tom :)