Need new harddrive

You have to use a hard drive with the same connection type, but you can upgrade, and brand doesn't matter. And yes, as long as you're using the new drive with the same machine, you can use your recovery disc. You say you know just enough to be dangerous around electronics; are you familiar with drive imaging? That would make you even more dangerous. If you have an external hard drive, or know how to split your local disk into two partitions, you could save an image of your operating system, then burn it to CD/DVD later. You could even split the backup into multiple volumes, in case the whole thing won't fit on one disc. Then, you could pop the new drive into your machine, format it, and "restore" the images onto the new drive. Of course most backups are not bootable; you still need the boot media for the backup program. But there are ways to get around this. For example, you could create two partitions on the new drive, load a temporary operating system, save the backups from CD/DVD onto the second partition, boot back into the drive imaging program, "restore" the image, and voila! If you have an external drive, it's even simpler.

If you would like to keep all of the same information on your old hard drive, as that of the new hard drive, then what I would recommend doing is using Norton Ghost. Now, Norton Ghost is an imaging software which can make a absolute copy of your old hard drive, and put it onto the new one. It is quite simple to use actually. If you have any questions, then just leave me a comment underneathe this response.