problem with sata HDD

[1SIMPSONS]

i have on my mb msi k8n neo2 platinium edition 4 sata conectors
i have 2x250 sata hdd in raid 0 {win xp}
my question is: can i make work another single sata hdd, (without loosing data on my raid hdd) {i can't see him in win) or do i have to buy another hdd and make another raid hdd configuration for them

thank you for any help

 

[tuskenraider]

You should be able to add drives in single configuration to the other two ports with no problem.