Hi my name is ***** ***** I will be the expert working with you today to help and resolve the problem you have posted.
you have windows xp and windows 7 as a dual boot computer?
if you have 2 operating system dual boot on the 500 gb disk you cannot use it as a drive you will have to build the ssd drive as c: drive and install windows either xp or windows 7 whichever you want.
Let me know if you need more info.
yes you can connect the ssd drive as a primary c drive and you will have to make the 500gb hdd to slave drive as d: drive.
Let me know when you are online i will give you more info.