Cobra, thanks for your support here.
Cobra is right in guessing that a reinstall might be the best solution here. These symptoms are unheard of, to date, which indicates that it's likely a result of some physical failure on your device (could be file corruption). It could also be indicative of the early failure of the SdCard (which is #1 leading cause of these one-off weird behaviors), as a failing SdCard can cause sporadic file corruption.
Reinstalling, often helps. If it then recurs, it often indicates the SdCard failure, and the fix is to replace the SdCard with another name brand card.
Next time you get it to run, and it starts misbehaving, please do the Menu => About => Send Bug Report, so that I can see the log, and please reference this thread or forums name here, so that I'll know who you are, and what symptoms you are reporting.