XP re-instal on from raid to single disk help

[pegasus1]

A mate whants to re-instal XP on his sytem and change his RAID (stripped) to two single disks, one for Windows and one for games.
Can he just removed one disk and re-boot with the windows disk and re-instal over the previous instal and thus save his previous settings.
Also if he does this will it keep the info (games and data) he has already.
Ive never used raid but ive a feeling he will have to re-format after backing up his data.
Any help and advice would be a bonus.

 

[pegasus1]

Cheers guys, ultimately he want to end up with 2 x HDD with no raid, one drive for Windows and Apps and one drive for games/music etc.
Ive told him to save his game data to a DVD (saves/patches etc) and then download the latest drivers for his mobo/gfx/soundcard then to do a complete re-instal of XP and once thats up and running connect the second drive and load the games and patches.