I have Fedora Core 2 installed in a 40 GB partition and I would like to install Windows XP in a 30 GB partition. How would I accomplish this?

*insert pain*

Windows takes over your boot sector, so you can install it (make sure you're installing it onto correct partition too) and then you have to re-run linux cd and boot into recovery mode, modify your bootloader config and reinstall linux bootloader again, as windows bootloader does not play nice with anything but windows. Also backup all your important stuff out of linux first too. Also if you are not very good with linux consider installing windows and then reinstalling linux as this way might be less painful for you.

you might have potential problems. XP is not good in sitting besides Linux. Personally, I've always installed XP first and then anyother linux. But there are people here who must have done the other way round.

Sorry, cant offer help although I'll be interested in knowing how to do that.

Tux,

Edit:
Mikhail_16 got the better of me

if I were to uninstall linux but keep one partition with all my configuration and then later reload that onto my newly installed linux would that work and how would i keep all my config??

Unless you installed a lot of custom software (and i doubt you did) you need to backup few directories, namely, /etc (>97% of configs) /home (maybe few more configs and all user files) and [optinally] /var (rest of configs, databases if you have them, etc). backup those things to a different partition (alternatively, just burn the lot on a CD if you have the ability).

Then install/reinstall all you want, BUT make sure to keep that backup partition safe. then when ready just copy all the stuff from backup back to where it belongs overwriting everything. and you SHOULD be back to the original config (be careful with bootloader configuration though, consider skipping it altogether, or not backing up /etc at all as it contains only config files).

/home is the most important directory for data retention, unless you did a lot of custom configuration on your machine. /var is second in importance in terms of data retention as it contains mysql databases and apache webpages if you are using them.