The personal statement is also a great place to explain more serious problems, like less_than_ideal grades or test scores. Don't be afraid to write something like, "I don't test well" in the statement. As long as you can provide a good reason for you app's problems, it's okay to address them directly. You won't be able to hide it from admissions officers anyway, so providing a reason for problems is always preferable to ignoring them.
Focusing on negativity _ People face problems from time to time; however, there are those who have faced graver trials than others. If you are one of those people who's had your fair share of problems, make sure that you adopt a positive attitude despite the challenges, and reflect this attitude in your statement. Wallowing in negativity will give off an unfavorable vibe, and enumerating all the trials you've been through will no longer make your essay an interesting read.