As you may be aware I'm posting the whole Chapter 1 for the PSM1 via Google Docs. This is not only for everyone's peruse (is that a good or bad thing?) but also mosre importantly: as a form of backup.
Backups, if done properly, can save you a lot of hassles as well as preserve your (and probably other's) sanity. Hard disks, being mechanical, have higher failure rate than other parts in your PCs. I once had a problem with a partition storing my photos when it suddenly failed to be detected, but luckily I had a DVD backup from which I recovered them. Nowadays I make multiple copies of backups for my pictures.
So I strongly recommend everyone to back their PSM files up onto multiple destinations. If you are using Bloggers, chances you can also access Google Docs as well. You never know what will happen to your laptop, so better play safe.