|Does the drive show up in device manager? If so, it may be your computer isn't mounting the partitions. I had the same problem on my desktop, device manager wasn't "Populating" the volumes of the hard drive. If there is no device listed, restart with the device connected. If it works now, you know it is a plug and play problem. If it isn't there, the problem may be a bad USB port.|
If the hard drive has no power cord, (Powered by the port), it may be that you are plugging it into a non powered port. The easiest way to fix this is to buy a powered USB hub. Many older laptops have non powered USB ports. (I can tell your laptop is older because it has 512 Mb. Ram).
Pentium 4s - The processors for the rest of us.