There are lots of things you can do like INSTALL programs that block virus' and malware, block cookies, use a secure browser, change your password often, delete browsing history, but spyware and intrusive behaviour systems are everywhere and they are getting better.
For example your bank will have on-line banking. On their website the address will start with "https/...." and your computer will inform you they this site has been verified by VeriSign (or similar organisation that makes sure this has been registered and it is what it says) This is important because thieves are clever at copying the real website and they can make it look exactly the same but they can't use the real website name. What they do is make it look the almost the same.
You then log on to your bank by using your account number (we hope you didn't throw your bank statement in the rubbish) but even if someone has your account number they do need your password which you now put into the log in. some banks don't let you in until you complete the second security check. This might be another way to identify you to the banks computer. If you do not get everything correct you may get up to three chances to correct it before you a blocked by their security system and you will have to go personally to the bank to be recognised and to reset your security.
Another good thing to do is to limit the amount of money per day that can be transferred out of your account to anyone else. You can change this but do not forget to reset it after.
When you do contact your bank they will ask you to tell them the amounts you have spent before your card was stopped. (Always keep receipts) This help the bank to know what payments are made by you and when the thief started using your card. Most banks cover the cost of purchases not made by you.
Use better passwords. Computers can find a password by trying thousands of combinations that's why banks stop your access if you fail about 3 times. Simple password are easily hacked. Some people use their name of some even use "password" as their password. A password that would take years to hack and is simple to remember consists of a combination of capital and lower case letters, numbers and keyboard symbols. Here is a couple of examples. Monkey (weak) can become 2Mo3nke2Y* (very strong) and Arigato becomes 4Domo3*Ari4gato* (very strong)
For how you protects your family and personal information please see others posts