Transfer Photo Database To New Hard Drive
There are various ways of going about it:
1) The method linked in the previous reply. Basically copy everything over without worrying about drive letters, then starting up Lightroom (you may have to point LR to the new location of the catalog file. Alternatively, double-click the catalog file in the explorer and LR will open it automatically), go to the folder list of your catalog (left panel in Libary mode), right click your photo-folder(s) and select "Update Folder Location". You can now point LR to the right folder(s) on your new drive.
2) Install your new drive as G:, copy everything from F:, remove your old drive (or change its drive-letter) and set your new drive to F:. Now all files and folders have the same path as they did before and LR should run fine.
3) Start with switching your old drive to G: (or anything above). Install your new drive and set it to F:. Now copy the contents from your old drive to your new one and you're ready to go. You can leave the old drive in or remove it alltogether.
Option 3 is the easiest. If you want to keep your old drive as F: for some reason, then you'll have to go for option 1.