Along with the super excellent advice posted above, please consider:
Linux w/Skype, TAILS, Free/Paid VPN, physical security and parental supervision requests.
Get your brother a fun job with the NSA and move him up to Fort Meade, Maryland or an interesting foreign posting.
If your your computer has been hacked, you might consider having a Malware Removal Helper assist you in mitigating any residual malware, which includes spyware.
Once your system is determined to be clean, please consider blocking a hacker's computer IP address and elevating all manner of security precations.
If you employ a Wi-Fi connection with your home's router, you might insure that the use of WPA2-PSK encryption is enforced and change your password(s) to those that challenge common password cracking tools. Some of this does not preclude a hacker's use of a Wireshark type of monitoring application though. Consider using convoluted password phrases versus words.
Yes - as gently and politely as we can be nubeman, please do improve your grammar & spelling. As a parent of grown children, I can directly corelate their life successes to their length and depth of education.
Edited by 1PW, 30 July 2014 - 04:25 PM.