Last week was a mess for me - my laptop and I thought my disk drive had crashed - and I lost about two days of work because of it.

For the past several days, Vista had been operating sporadically – applications locked up or wouldn't open, Windows Explorer wouldn't work and performance was slow, slow, slow.

Fortunately, I had installed Carbonite online backup, so I was able to verify that the files I was working on were being backed up. I also checked to see that files had been backed up locally to an external USB drive.

Carbonite costs $49.95 a year and backs up files as they change. The service backs up as much data as you want. It is well worth the investment as I found out last week.

Anyway, on to the story. After I verified that the files I needed had indeed been backed up by Carbonite I ran a low-level disk utility to find that my hard disk was OK. I also ran my virus protection software for the thousandth time to make sure that an errant virus wasn't affecting my performance.

Then with fingers crossed, I shut down my laptop – I had been reluctant to do this, since I didn't know if it would restart and I had several deadlines to complete.

After shutting down the laptop, I inserted the first of my system recovery disks – consigned to the fact that I might have to re-install applications and data. The system quickly ran the first three disks, and restarted. I entered my password and found that only Microsoft Office 2003 had been clobbered. I reinstalled it, and also found that my data was still there.

I can't say that Carbonite had saved the day for me, but I am definitely glad I had it installed on my system. If you want to find out more about Carbonite's online backup service, visit its Web site (Compare Data Backup and Replication products)

Deni Connor is principal analyst for Storage Strategies NOW.