My external hard drive not working

Portable Drives My Passport
1

My external hard drive is spinning but the lights arent coming on and it doesnt show up in my computer. this was in windows 7.  it seems to work on windows xp.  does any one know how I can get it to work on windows 7?

2

tried it in another windows 7 pc and one light comes on now, but its still not recognised in my computer. any help will be appreciate it. thanks