cant find HDD

Hi I have 3 HDD on my pc one of which i felt was causing a problem with my pc freezing so i ran my pc with it disconnected for a while and it seemed fine. I reconnected it the other night and virus checked it with norton and it found over 4000 trojan horses on their which i qurantined, these were also found on my c drive which i had virus checked the night before which was strange and as the hdd was not connected power wise i thought it wieird. anyway i took some music off the drive i needed and disconnected it again i have tried reconnecting it now and it shows up in my bios and device manager but not in my computer, device manager says it is working properly and if i go into disk management it shows the drive with a no entry sighn when i click reactivate drive it tells me their is an invalid magic number in the configuration copy ? anyone got any ideas, thanks dave

 

Might be good to post this in the malware removal section.

4000 trojans. DAMN!