BOOT TIME SCAN ---what it's all about?

What exactly is a boot time scan? When do i need to execute a boot time scan?
Does this scan help in detecting hitherto undetected/hidden viruses in the system?

To quote another…

Hope this answers your question,

-Scott-

Boot time scanning is a full scan before Windows loads, i.e., when you can have full access to all files (no one is “running” by other application).

Well, that’s not 100% correct… I mean, the boot-time scanner is running, so other (similar, special) applications may be running too, and of course some (malicous) drivers can be loaded.
But yes, it’s running quite early in the boot process, so ordinary applications are not running yet - so there’s a chance to detect/remove some stuff that may be hard to find/remove later.

Well, time to release a free CD for on-demand scanning… maybe the promised new Bart CD with a pro and home (free) versions.

Can boot-time scan be a substitute for scan local disks?
I mean, what if whenever i’ve to scan my system, i just go for boot-time scan straightaway, and not bother about scanning local disks. Will that do?