Protected Storage Service

I have recently installed an extra Scsi drive into my NT4 server, but have found that I am unable to delete the existing NTFS partition (second-hand drive) due to an error that states ‘Unable to gain exclusive acces to drive’. I cannot down the server to clear whatever it is, and so have started looking to see if there is a service that has locked the disk. The only service I cannot account for is the Protected Storage Service. I can’t find anything about it on the web, and would just like to know if this is likely to be the cause of the problem and can I stop it if it is?