Mayman, you need to always check whether the websites you pay on have SSL certificates (the address should start with https) also the URL bar should be turning green or another color and if you click next to "https" you should be able to get the certificate detales.
If you get all the above then you are safe.
As per PayPal then no one has it on the company page as the link redirects you to PayPal page customized for your company (at this stage you should be able to see the https instead of just http).
Thomas, how come you went blue, you were red from what I remember.
And yes, use a decent antivirus. I'm a network security specialist so PM me if you need help.