It is only "more" secure if you have taken other precautions (BIOS password, and in windows, a password protected (or deleted) Admin account) at the minimum.
Other than Geek/Showoff value, then it's pretty useless. they are fairly simple to get past, as some kid locked all the Display laptops in work (Large Chain store in the UK), and I couldn't be bothered remastering them all.
A little googling, and presto (Live CD's and SAM files IIRC)



