1. make sure your use an updated anti-virus software to scan your machine, there could be spyware running on your box, stealing personal info from your machine.
3. You should go through your address book and use your another account to let your friends knows your account's been hijacked and don't trust anything coming out from your "old" email address
Hackers are everywhere. As a computer user, you will need to protect yourself. it's just like thieves are everywhere. For home, you'd install an alarm system to protect your belongings; for a computer, you'd need a powerful and updated anti-virus system to guard your data.
don't think that should be required. Usually if you are setting up a mobile device to read your hotmail, then you may need a PIN (personal identification number). in your case, you should be able to keep that empty. give that a try.