I keep getting locked out of exams or timed out right when I start an exam.

If you have problems initially accessing an exam or survey "double-clicking" may be the problem.
If you double click on the link to the exam, you will get the message that you have already taken the exam. DO NOT double click anywhere within blackboard. The only solution for this is for the instructor to reset the student's exam so that they can access it again to actually take the exam.