We first came to know that Microsoft is coming to our campus through our placement cell. They were offering three intern positions: Software Development Engineer (SDE), Software Development Engineer in Test (SDET) and Software Management Engineer (SME). The first round was a written test. It included questions on arrays and strings (reverse the words in a string, swap an array in a given way), a few puzzles. We were also asked to write test cases for Excel and a couple of management related questions were thrown in.
After the written test, there were three interviews, all one-on-one. In the first round, candidates were asked about basic algorithms and data structures(trees, linked list manipulation). A few puzzles were also asked. I was also asked about Microsoft's products and services. (Which ones can you recall? Which one do you like most?) The second round was HR based questions (family background, ethics, scholing, college, etc.). The third round was again HR based - Strengths, weaknesses, why Microsoft.