Cloning whether SATA or IDE is fairly straight forward so long as jumper settings of the hdd's is correct ,one hdd set as master the 2nd hdd set as slave,that's assuming your cloning, as you mention having to reinstall xp which is not the same as you need the original xp disk to do that,it's important to get the terminology correct as it makes the topic confusing & that includes naming of disks,so i'm to assume you have the following
1)-Master HDD = contains the original xp prof installation & partitions that you use to transfer to another hdd when shit hits the fan
2)-Slave HDD = is used to clone to
Remove cables to Slave hdd & check Master drive can still boot
EDIT: I'll help all i can as i am reasonably familiar with cloning i've also had an issue where my drive letters were all stuffed up,that came about by incorrect jumper settings if memory serves,there's also this site if you need more expert help it's called radified,nightowl & co specialise in cloning issues,all advice is free.
WWW LinkEDIT:2 To test run kubuntu or ubuntu you can use microsoft virtual pc 2007 & run it in a virtual pc,it works great but there's a couple of things you'll need to read to install it's relativley straight forward,basicly it's how to capture the mouse poniter
http://arcanecode.wordpress.com/2007/10/22/installing-kubuntu-710-in-virtual-pc-2007/
http://www.woodwardweb.com/programming/000387.html