Problem with removable hard disk

[Biel1718]

I have a HP nx7400 laptop, and i want to connect my 250 gb hard disk, but when i connect it, the windows is unable to find drivers for it. It says unknown device . So any suggestion guys???
By the way i have the same problem in build 7077 and 7100

 

[Martin]

what kind of external is? i had a problem with one WesternDigital, i resolved by installing an wd application. look a this http://www.sevenforums.com/drivers/6185-wd-1tb-not-recognized.html