how to remove 9.04 so I can upgrade to 11.04

When you install the new system choose to erase the old system and install only the new on the HD.
Have you checked the hardware requirements?

Take a look here:
https://help.ubuntu.com/community/Installation/SystemRequirements

Thanks for the speedy response. System requirements OK.When I put in the 11.10
CD it pops up in a window headed "cdrom0 file browser". Never seen a box like
it in Windows (sorry about the W word). I'm used to loading programmes that
auto boot, no idea what to do with this box. John

Quoting "Enrico \eNry\ Carafa" <email address hidden>:

> Your question #179088 on Ubuntu changed:
> https://answers.launchpad.net/ubuntu/+question/179088
>
> Status: Open => Answered
>
> Enrico "eNry" Carafa proposed the following answer:
> When you install the new system choose to erase the old system and
> install only the new on the HD.
> Have you checked the hardware requirements?
>
> Take a look here:
> https://help.ubuntu.com/community/Installation/SystemRequirements
>
> --
> If this answers your question, please go to the following page to let us
> know that it is solved:
> https://answers.launchpad.net/ubuntu/+question/179088/+confirm?answer_id=0
>
> If you still need help, you can reply to this email or go to the
> following page to enter your feedback:
> https://answers.launchpad.net/ubuntu/+question/179088
>
> You received this question notification because you asked the question.

boot from the live cd and then open the disk monitor tool. your hard disk info will be displayed there. choose the option to format the drive. format the entire HDD. restart and then go ahead with fresh install.
you have another option too. just boot with win xp cd and just proceed up to formating the harddisk. format the entire hard disk in ntfs or fat. then start installing ubuntu.