[bluenette]

My laptop's USB ports don't work. I tried plugging in my Seagate harddrive and my laptop doesn't read it. But it sometimes reads Sandisk Mini Cruzer ones. But my wireless mouse adapter works. I don't know what to do. I checked if my ports were working properly in the systems section in my laptop and it said it was working properly.

[the.user]

If wireless mouse adapter works, and some of the flash drives work, I'd say its the HDD that isn't working.

[bluenette]

If wireless mouse adapter works, and some of the flash drives work, I'd say its the HDD that isn't working.

what does HDD mean? thanks for the reply.

[the.user]

HDD = hard drive.
Have you tested it in any other computers to see if it works with them?

[ChunJin]

Are you using Windows Vista, XP, 7 or Mac OSX (if so what version)?

For Windows:
The best way to fix this would be to:

0 - Connect your External Hard Drive to the PC.
1 - Go into Control Panel (click start/windows vista button then click control panel)
2 - If in Vista click "Classic View" on the left and find an icon that says: Administrative Tools. Double click that.
3 - Then find an icon that says: Computer Management. Double click that.

It'll bring up a new window called Computer Management.

4. On the left tree menu, find: Device Manager. Single click that.
5. After clicking it, the main window will refresh with your PC and components.

Look for [+]Universal Serial Bus controllers, and click the [+]. After it should expand the list and the [+] should turn into a [-].

6. In the expanded menu look for: mass storage (your hard drive). When you find it, right click and click "Uninstall"

This will uninstall the drivers and what-not associated with the Hard Drive.

7. After it's done removing the previous drivers. Unplug your External Hard Drive, and then plug it back in. It'll go through the procedure of saying "Found New Hardware" and will search for drivers. It'll install by itself.

If it did install correctly, it'll say so in the lower right. After that, back in Computer Management go to Disk Management and your External Hard Drive should be displayed in there.

Then it should be working... If not, then your hard drive probably died.

[endlessdeath]

I had this problem too just a few weeks ago,
It could be that your laptop cannot supply enough power to your External Hard Drive.
(This is true actually, or at least according to my friends, because it did happen to them too.)

Some computers/laptops only supply 500mA of power through USB ports, and some External Hard Drive (you should check yours) need 1000mA of power to work.
If your laptop does supply only 500mA and your hard drive needs 1000mA you should get yourself a Power Booster Cable, not sure if that's what it's called, but it's the cable you use to have a separate power supply to your hard drive, so there will be enough power to make the hard drive work.

By the way, have you tried plugging your Seagate Harddrive to another computer? It could also be that your hard drive is broken.
You could PM me if you have questions too, but if you already found a solution, good for you.

Glad to be of service!