The current drive is 30Gb – Will I be able to use 60Gb?
that depends on the BIOS but probably yes.
Are 2.5” drives all the same size externally. It’s a very snug fit! How do I know whether a new drive will be compatible?
No some drive are slightly thicker they come in 9mm or 12mm heights make sure you get one that fits.
I have the Samsung-supplied XP re-install CD (not full XP). Will I be able to use this on a blank drive and I assume that, with a new drive,
If the restore disk activates a hidden partition on the HDD to reinstall windows then you may need to purchase a new copy of windows and find all the drivers for the equipment in the laptop.
you can back up the drivers and save to a pen drive or cd before you take out the old HDD.
Driver guide toolkit will do that for you. click here