Since other people run X and CX with ME successfully and you've reinstalled everything several times over, we can conclude that there is a fundamental problem between Xara software and your system.

Some questions need answering:[*]Did you try running Xara before reinstalling any other software?[*]Do you have anything running in the background (e.g. virus, firewall etc.)?[*]What additional hardware do you have (e.g. scanner, camera etc.)?[*]Did you run Xara before you installed the extra hardware?[*]Is there anything about your hardware / software that is non-standard (e.g. language, accessibility)?

Faced with this problem, I'd remove as much as possible until I got X to work, then add bits until it stopped working.

Regards - Sean