Maxtor external storage 1000gb wouldnt show up on pc

[olgaddt]

and yet it was working fine but only on some computers a week ago. it would make the noise and green light in on but nothing happens on pc. how i can fix it or who could repair?
thks
Olga

 

[RealBeast]

Check to see if it is recognized in Windows Disk Management and also if it has a drive letter assigned.