Thanks for the replies. I know for sure there is no other user on my system who is trying to use my computer to access this forum website.
As to the question of static or dynamic IP address, I have to conclude I have a static IP address, one that does not change.
Some time back, a hacker tried to extort money from me, threatening to reveal my online browsing habits to all of my contacts. The hacker stated he had installed a key logger on my system...which I have a vague idea of what that is.
I need to a) make sure I identify and remove any such malicious software from my computer, and b) ensure I am protected against similar threats in the future.
I have Avast firewall software installed...do I need more protection?