This post could go in many categories but I chose this one because booting to a LiveCD for maintenance is often done in a security driven scenario.
You often need a way to interrogate a system outside of your windows installation. Until recently the choice has been BartPE (free but difficult to configure and build), Linux Live CDs (which are great for linux users but scare Windows people and don't offer full NTFS support) , ERD Commander (great but prohibitively expensive if you aren't a Tech in a large corporation) and Avast BART cd (again very expensive for a home user or mobile tech). Now we also have active@ Bootdisk V3 which is $70. It includes a disk imaging program (which can handle dynamic discs), good hardware support as it's built on Win-PE v2, data recovery software which I have used many times in the past and can attest it's usefulness and well lots of @Stuff@ which is just useful (like term services client, hex editor, partitioning software).
You could certainly make a BartCD using BartPE which would be better if you got the time, the skillz, lots of software and a lot of drivers hanging about. For $70 it rocks - I am posting this from a Active@ session and it is sweeeet!