EDIT: SHOULD READ 70-685 (typo)
After passing my 70-680 yesterday

, I was due to tackle the 70-685 today.
Got to the test centre on time, and off I went with my 70-685 exam.
All was going fine until just past halfway when pc locked up and crashed - unable to progress further.
After some Prometric help, test restarted but was different set of questions - unable to resume first attempt.
On second attempt, all was ok until about 75% of the way through, when same question crashed again.
Test abandoned due to insufficient time left.
Prometric are willing for me to re-register the test and try again.
I raised the issue with Microsoft and they suggested I raise a Challenge form.
I've done this but this is not just a challenge against one question.
Is Microsoft able to award a pass/fail result against questions already done prior to the problem.
e.g. I have done over 57 questions today to no avail.
Any advice please with regards this?