Start with the basics: Do not allow people access to your computer or if they use the computer, do not allow them access to your User Account. Set a password to access your own User Account. Periodically, start computer in 'safe mode' and run a scan to see if any spy bot software is on your computer. Use an Anti-Virus product which offers some Web Browser protection just in case you click to open a bad website and it can block it or warn you about it asking should it proceed or not. Don't download anything you do not need to download. People sometimes forward what they think are 'funny' emails to family and friends, but fail to remove all the email addresses from the header info - therefore forwarding other peoples personal data eg: email addresses. The trouble is it is endless and keeps being spread around, so who knows who ends up having access to other peoples email addresses. Those types of emails could have been initially created by someone with the intention of collecting email address. Do not forward on that kind of email. In Thunderbird you can help to improve security. Do not allow remote content to be displayed. By default this is switched off. https://support.mozilla.org/en-US/kb/remote-content-in-messages Do not auto use the 'Display Attachments Inline' - only enable if you are absolutely sure who sent the email and it contains only eg: family images and remember to switch it off after use. Just because it says the sender -From- is someone you know, does not mean they were the real sender. If email does not look like that person would send that sort of message then be wary. Check the full headers to see who originally sent it. Note the 'REceived by: header nearest the top will be your server, so as you read down you can see it passed via other servers. That means the data in the REceived by: which is closer to Date, From, subject ,To headers and also the message is the one who sent it originally. Do not click on links whether text or image without being fully aware of the true link. Hover over link first to see real link data in bottom Status bar. Just because it says eg: 'Click here to Logon to account' does not mean it's directing you to the correct location - the link might say in reality it goes to : CuriosityKilledTheCat.com and give me all your passwords - if you get my meaning ! Some emails can look convincing because the sender has copied a genuine email and then maniputated the html code. Never, be tempted to open any attachment if you are curious to know what it is. I've had plenty of bogus people sending me emails saying your Invoice is attached. Do not be conned. These people are hoping you will be curious and you have no idea what that attachment contains. You do not want to accidentally install spyware. If someone rings you saying something is wrong with computer or router or a fraud is detected etc.... do not allow them access to computer - do not download any app just because the stranger says do it - you do not know who is really ringing you - be suspcious. Do not offer any passwords, not even your name because it's likely they do not know who they are talking to and that's why they are trying to gain your confidence. be aware that your email address could be on a friends computer and it might be their computer which gets hacked. If you ever decide your computer is naf / broken /dead / etc. If you can you should reformat the hardrive before binning it. If that cannot be done on that naf computer - remove the hardrive - then use appropriate cables to gain access it to it via another computer as if it were an external drive. Then try to remove all data. Finally smash it up properly to prevent someone using it. Do not just bin it thinking it is dead. If you store contacts elsewhere on someone's server eg: Google, OneDrive which is Microsoft, etc then you have to hope they don't get hacked.