I just did this last month and was new to it. But I can give you the info that I found helpful.
Flash your Bios: To do that just Google "BIOS" with your Computer type and you will see it on the list. Then make sure you have a drive with an ATA or IDE (it is the same) interface. You will also need some cloning kit to get your OS and current setup onto that new drive. Download Arconis Migrate Easy trial version to clone your drive. The software that I got with my cloning kit was showing the same low capacity on the new drive after I cloned it (10gb) which meant that I had to start over and clone it again (with Arconis.) It takes a minute to clone high GB, so that stunk. Other than that it is easy. Good luck.