Here's all the information that I think the project manager should know before starting any project:
- Who is the project client? Is he a new client? Is he a previous client? And if he is a previous client, did project managers have good or bad experience with him?
- Who are the stakeholders of the project? What is each stakeholder's influence? Who is the project sponsor?
- When does the company intend to start the project?
- When is the deadline to finish the project? Is the deadline feasible?
- Who will work on the project? What are the available (and suitable) resources to work on the project? How many people are needed to work on this project?
- Are the resources who will be assigned to the project also working on something else (another project? other routine tasks? etc...)
- What are the major risks involved?
- Where is the project going to be executed? (Is it on-site or off-site?)
- Who is the project manager going to report to on this project (is it the project sponsor? Is it the program manager?)
- How is the project manager going to communicate with the team members and the stakeholders?
- Was the project attempted before and killed?
- What is the allocated budget? Is there a possibility to go over budget?
- Are there any project management standards (usually specified by the PMO)?
- Is the project going to need materials/equipment/software provided by 3rd party vendors? If yes who are these vendors? Should we setup new contracts?
- What is the expected ROI of the product or service that will be created from this project?
- Is the project aligned with the organiztion's objectives? (Clearly this is not the project manager's responsibility to answer this question, but it's usual for project managers to ask this question, as it's a first indicator on whehter the project will be canceled in the middle of the road if it's not aligned).
There are many other questions to be asked before starting a project, but these are the ones I can think of at the moment.