What The_Headacher answered is correct. You need to use it at each boot.
The Livecd versions of VL are great to install on very small hard drives or pendrives 1-2Gigs you can run a full VL OS and save changes to the remaining freespace.
That could work out perfectly. Some of the kids we work with don't even have a place to keep a computer. This way, they can carry their 'computer' with them on a USB stick.
Laptop: IBM X60s (Centrino/Duo, 2gb ram, 80gb hd) VL 6.0 Std
Netbook: HP Mini (Intel Atom 1ghz, 2gb ram, 16gb SSD + 8gb flash ) VL 6.0 Std
Desktop: Dell Dimension 5150 (P4 3ghz, 2gb ram, 80gb hd) VL 6.0 Std
Wife's Desktop: Gateway (P4 2ghz, 1gb ram, 80gb hd) VL 6.0 Std