Hidden Partition question

Hi Recently discovered the forum. Inspiron 630m, XP with 10Gb FAT 32 partition for sharing between Win and Kubuntu (currently using Feisty). 20 Gb Reiser partition for Kubuntu. Tend to load Win only to update and to use Dragon Voice Recognition (for me the killer app). Everything else, I use Kubuntu for (including Quicken 2002 standard, which runs great with Wine). My question- the "hidden" partition (sda3 - 4.6Gb with 3Gb used) is seen by Kubuntu. I did not elect to get the Win XP disk which after buying the laptop I learned I could get for a further £5 IIRC. Can I burn the hidden partition to DVD for restoration say in the event of hard drive failure? Or is this doomed to fail. Also, some time (a couple of months) after I bought my laptop I got 6 disks (5cds and 1 DVD) For "Reinstalling". These arrived without warning or explanatory notes. To quote the DVD (for OS reinstallation) "The software is already installed on your computer. Only use this DVD to reinstall the Operating System on a Dell PC". The 5 Cds are to reinstall software and drivers and utilities. I confess to being confused here, as this would suggest I could (say) buy a new HDD and start again from scratch. Would that be a correct assessment or am I (as I have read elsewhere on this forum) going to have difficulty as the Dell Restore utilities require the MBR to be as per the original. I ask out of curiosity mainly as the way things are more likely to go for this machine is Linux only, at some stage. Thanks Ian