Incremental Windows Backups

I am trying to make incremental backups of my Windows XP x86 and x64 OS's to allow fast recovery at the time of a boot drive failure.

I first did an incremental backup (not sector-by-sector) but OS recovery failed as boot and registry information is not copied.

Then, I made my first incremental sector-by-sector backup (full BK as it was the first BK) with compression right after XP was installed with minimal drivers and updates. The backup was about 60GB.

Two days later, after I installed all the updates, drivers and few programs, I did another incremental sector-by-sector backup. Now the backup is about 65GB.

I thought that the incremental backup would be relatively small ~5GB. Is there are a need to do a sector-by-sector backup after the first one to allow full recovery to the most recent image? Is there a preferred way/routine to make incremental backups of the OS? Also should I do incremental or differential BK?