Ok, first things first.. lets disuss Software hacking and tracking...
To be honest, if you have any reason to suspect that someone knows what your saying, doing, or reading online.. And if that same someone is the same someone who provided the computer..
Chances are that they did install something on the computer.. Theres so many free and paid programs out that that can steathily spy on you in so many different ways, It would take days and days to discuss and describe them all...
The safest and surest bet, is for us to take the time to save anything important from your computer.. Pictures, important word documents or work files, and once you have everything that is irreplaceable saved to either an online storage site such as google drive.. Or saved to an external hard drive, or cd / dvd..
Then we should factory wipe and restore the computer.. Doing so, will wipe out anything user installed.. I( whether that user was you, or the other person who had the computer before you did)
Thats a sure fire way to get rid of any tracking programs.. And to be 100% safe, that covers about 30% of what we should do..
next, we should consider that if there were any keyloggers installed on the computer.. ( example below)
We have to assume that every email account and social networking account ( facebook myspace, etc ) That its entirely possible that someone else has your passwords and has access to them..
A smart hacker, wouldnt change your password or do anything that would alert you to the fact they were accessing your account, so you would never know it was happening other then people being aware or knowing of things they couldnt or shouldnt be knowing..
So our second area of focus is Immediately and systematically changing all the passwords to your email accounts... And not just password.. You need t o review your account recovery options ( the options you use in case you have lost your password or need to reset it)
Sometimes a hacker will add their own email as an account recovery option, so that if you change the password they can get into the account again.. Also , mobile phone numbers are sometimes used to reset the password via a text message.. And the most vulnerable area are the security questions..
If your security question is, Who was my 4th grade teacher and if thats something that your ex, or any of your friends could possibly ever know.. the answer is a gateway for someone to hack into your accounts..
the best security answers are nonsensical ones that you will always remember.. For example, Security question = What was my mothers maiden name
Secure answer = ironmaiden ( something no one could possibly ever find out, or guess)
Youll want to systematically do this on all accounts you use.. Make them asolutely secure.. ( but only after )
We have done a factory reset on the computer itself, wiping everything and reinstalling it. ( which is a whole lot easier then it sounds)
If we change the passwords and security info now, and theres a spying program or keylogger on the computer.. they will simply see and know the new password.
That covers about 70 percent of what we need to do... i dont want to get into the low jack part yet, as the ground above is already quite vast and im sure that we may need to communicate back and forth to implement each part above in depth...
I have to send this as an answer, however, you dont have to rate the answer yet since we still have a bit of back and forth and questions to be asked and answered before we can say this is complete..
that being said, if you have any questions about the process stated above, the neccessity of it, or anything relating to this issue please feel free to ask...