HDD Swap malfunction

[Chriss1784]

i recently swapped out the stock 60gb hard drive from my sony vaio s580 for a new 120gb disk. I also purchased a kit to turn the old drive into an external. to test the kit i used the new 120gb and it worked no problem with xp. I have installed it to the machine and it is working fine, however now with the old 60b in the external case windows wont recognize it. I had cloned the drive so im thinking maybe it is just confused from seeing two hard drives exactly the same, or perhaps i just need to format the 60gb drive. If that is the case though, i would like to ask for some help on how to format it if i cannot get it to be recognized. any help would be very appreciated. thanks