I bought an external HD with an eSATA port, connected to my laptop with eSATA port, and Vista does not detect it. Why?

"Its possible that Windows isnt recognising the drive because its not formatted in a standard Windows filesystem. For example Windows uses the NTFS or FAT32 filesystem.

If Windows cant read the drive then it probably will not pop up in My Computer, but it will still show up in Disk Management. To get to this;

Right click on My Computer
Select Manage. You may be prompted by UAC, just press accept/ok.
Once its up, on the left you want to click Disk Management.

This will show you every drive that Windows knows about, regardless of what filesystem its running.

If your drive appears here, you need to right click on it and select format. Check that the filesystem is NTFS, and hit OK. After this is should appear in My Computer as normal.

Ok, the problem could be one of these three things;

A problem with the eSATA cable
A problem with the eSATA connection on either the hard drive or PC.
A problem with the eSATA drivers on your PC.

First I would reccomend trying to plug the drive with the same cable into another computer. If this works it rules out any problem with the cable and/or the hard drive.

Then I would re-install or update the eSATA drivers. To do this you will need to go to the website of the company the made your motherboard, and search for the drivers there."

"eSATA does not provide any power to the device. Make sure that you have an external power adapter connected to your external hard drive in addition to the SATA cable.

Also, technically you are suppose to use a special eSATA cable that provides more shielding than a standard internal SATA cable."