Hi, first of all I would like to thank you for contributing how-to's so that newbies on Linux like me can learn y take as reference. 
Thank you! for that..
Now you have got every thing messed up.. but now.. 
first of all keep the linux boot disk handy
Secondly.. take the windows installation cd and load windows recovery console by booting your computer from installation  cd of winXP.. 
There it will ask for password of your windoz administrator  then run the following command !!
fixbootand 
fixmbrNow windoz will load normally...
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Now boot linux from linux boot disk ...
Open your /etc/lilo.conf and add following lines to it.. 
lba32Now again follow the above steps...  but do not ever try to edit bootsect.lnx... 
You will be fine...