As far as i'm aware most people take their MCSA on the way to MCSE.
MCSA is normally 4 exams and MCSE is a further 4 I think, check the MS site to be sure.
The MCSE is quite advanced so really most people should go for MCSA first as a first step.
I've never failed an exam 'yet', and i suggest you don't either !
Far as I'm aware you are allowed two attempts and then you have to wait 2 weeks before a further re-take? I'm not aware of any limit on the number of attempts. As with everything check with M$ site to be sure, its explained on the exams conditions when you take an exam but I normally skip that these days.
I expect an MCSE will be along later with a better explanation !
