That depends on what you tell the installation to do. If you tell it to format, partition and bring you a cup of coffee, then yeah, you'll lose all that stuff. What is it telling you will happen? I believe you can perform a "new" installation vs a repair install and it will keep all your stuff for you. BUT, if you get a cup of coffee instead, don't blame me
I tried to reinstall windows xp , but because i have two partitions i now have 2 OS on my computer , both windows XP , if you want to reinstall your windows xp , just choose repair mode , it 'll save you a lot of problems
it's supposed to make the system in the same state as when the backup was made so i think it should work. Just choose the earliest repair-point there is. Just copy your important files to the other disk and you'll be fine.