The problem described by Zigurds(the customer) is that of making usage of the free space that he partitioned for Windows Xp to Ubuntu 10.10, possibly without deleting and reinstalling any of the OS.
After researching i have been able to devise 3 possibilities:
1. Using Parted
Program designed to manipulate partitions. It is possible to use either use this program by installing it on Linux or by using a boot disk (also covered in link).
While this is a valid option and shrinking a partition over the limit, where it may cause data destruction, is stopped and given a value that won’t cross that limit, it can have slip-ups.
There are also versions of graphical interfaced programs based on parted, one of them being Gparted.
2. Windows Disk Management
A nifty tool that allows you to do resizing, deleting and destroying partitions from within the Windows environment.
The second option is to resize the Windows partition, then using Gparted to create another partition for Ubuntu(or merging them). It is recommended to do a defragmentation before atempting this.
Any attempt of partition manipulation should have as a side plan a backup of the systems and/or files in question.
3. Uninstalling Ubuntu
While the customer may not want to try this i would consider this to be the best option, considering that a backup is mandatory.
It is considered preferable to install Ubuntu after a Windows installation. So what i would suggest is to uninstall Ubuntu, resize Windows with the Disk Management utility, then use the Live CD to reinstall Ubuntu using the “largest available free space” option.
Hopefully this helped you Zigurds,