NB asked me about precautions for banking online.
There's no perfect guarantee that hackers won't gain access to your accounts, just as there's no perfect guarantee that a pickpocket won't steal your wallet. Even if you never bank or make purchases online, your information can be stolen from a store or restaurant you've done business with.
But following these precautions will significantly lower the risk:
Keep your PC clean. Install effective security software and keep it up to date. See Remove a Virus or Other Malicious Infection, One or Two Anti-Malware Programs, and The Cleanest Malware Scan for recommendations.
Be careful of e-mail. Someone may be phishing. At the same time every month, my bank e-mails me a notice that my statement is available online. Although there is nothing suspicious about that e-mail, I don't click the link it provides. I independently go to my banks' web site.
Don't log on if it's not secure. Make sure the bank's web site is secure before you enter your password. The URL should begin with https: rather than the more common http:. Both Firefox and Chrome put a green label at the beginning of the address line if the page is secure.
Use a strong password. The best passwords are random strings of numbers and letters. Avoid words and names. If your browser asks if you want to save the password, you don't. And don't use the same password for any two Web sites. If you don't think you can remember all those random strings of gobbledygook, get a good, encrypted password manager. I recommend the free and open source Password Safe.
Avoid public networks. Don't visit your online bank, credit card company, or retailer from the public WiFi network at your favorite café or library. Stick with a private home network.
Protect sensitive data. If you keep any financial data on your hard drive, encrypt it. See Avoid Windows Encryption to find out what to do and not do.