New "Other" startup account option.

Hi folks,

Does anybody know why an "Other" account login option has just recently appeared alongside my own during startup?.

It was never there previously and does not respond to any names or passwords, plus I don't think it was there after my last system update. Is this something to be concerned about as my computer occaisonally goes very slow whilst not seemingly taxing the processor, yet I can hear the drive sound as though its busy and being accessed. Any help or input would be appreciated.

Thanks,

Chris