Hard drive chatters for a long time whenever I go on the Internet

Question

For some reason, whenever I click on a new website, the hard drive on my iMac starts chattering (accessing) for about 30 seconds.  Also, at the beginning of every on-line session, it chatters for about a minute.  Also it will not do anything until the LaCie backup drive cranks up and gets accessed, which is about five seconds, usually.
The performance is fairly good, it at least works after a few seconds.  However, there are times when I wonder if it has been turned into some sort of robot spam machine or something.
Does anyone have any idea of what might be going on?  Is there a utility that will give me a rundown of exactly what is being accessed on the hard drives, and why, in real-time?  It's a 27" quad-core i5 from about 2010, and I recently upgraded it to 10.9.4 Mavricks (will do the OS update as soon as I go off-line).  Many thanks for all info and help.

Answer 1

ESET will convey no benefit and your Mac cannot operate properly with it installed. There is no product in existence that can prevent you from willfully installing a Trojan.
Although I try to be very careful, I got a very scary pop-up that indicated that someone had tried to encrypt my files.  My browser was locked up as well, and I couldn't even shut down the computer.
Next time that occurs, describe what you see or post a screenshot. If you cannot capture a screenshot take a photograph and upload it to this site using the "camera" icon.
From what you describe it was a lame attempt at defrauding you into paying a ransom to unlock your Mac. This is very common scam and yet another threat from which ESET cannot protect you.
"News" websites contain some of the worst garbage on the Internet, and that doesn't include the typically harmful junk advertisements they host.
My question, is there any anti-malware software that you might recommend?
You wrote that you try to be very careful with your Mac and what you do with it, which is the only reliable strategy. Third party products are an ineffective defense to protect you from the scum of the Earth or the "news" websites on which they appear. If visiting a particular site causes your Mac to perform poorly, they don't deserve your business. Shun them. Uninstall ESET first because it may be the problem's direct cause.
OS X already includes everything it needs to protect itself from viruses and malware. Keep it that way with software updates from Apple.
A much better question is "how should I protect my Mac":
Never install any product that claims to "speed up", "clean up", "optimize", or "accelerate" your Mac. Without exception, they will do the opposite.Such products are very aggressively marketed. They are all scams.
Never install pirated or "cracked" software, software obtained from dubious websites, or other questionable sources.
Illegally obtained software is almost certain to contain malware.
"Questionable sources" include but are not limited to software aggregator hosting sites such as C net dot com, Softonic dot com, Soft pedia dot com, Download dot com, Mac Update dot com, and others whose revenue is primarily derived from junk product advertisements.
Don’t supply your password in response to a popup window requesting it, unless you know what it is and the reason your credentials are required.
Don’t open email attachments from email addresses that you do not recognize, or click links contained in an email:
Most of these are scams that direct you to fraudulent sites that attempt to convince you to disclose personal information.
Such "phishing" attempts are the 21st century equivalent of a social exploit that has existed since the dawn of civilization. Don’t fall for it.
Apple will never ask you to reveal personal information in an email. If you receive an unexpected email from Apple saying your account will be closed unless you take immediate action, just ignore it. If your iTunes or App Store account becomes disabled for valid reasons, you will know when you try to buy something or log in to this support site, and are unable to.
Don’t install browser extensions unless you understand their purpose. Go to the Safari menu > Preferences > Extensions. If you see any extensions that you do not recognize or understand, simply click the Uninstall button and they will be gone.
Don’t install Java unless you are certain that you need it:
Java, a non-Apple product, is a potential vector for malware. If you are required to use Java, be mindful of that possibility.
Java can be disabled in System Preferences.
Despite its name JavaScript is unrelated to Java. No malware can infect your Mac through JavaScript. It’s OK to leave it enabled.
Block browser popups: Safari menu > Preferences > Security > and check "Block popup windows":
Popup windows are useful and required for some websites, but popups have devolved to become a common means to deliver targeted advertising that you probably do not want.
Popups themselves cannot infect your Mac, but many contain resource-hungry code that will slow down Internet browsing.
If you ever see a popup indicating it detected registry errors, that your Mac is infected with some ick, or that you won some prize, it is 100% fraudulent. Ignore it.
Ignore hyperventilating popular media outlets that thrive by promoting fear and discord with entertainment products arrogantly presented as "news". Learn what real threats actually exist and how to arm yourself against them:
The most serious threat to your data security is phishing. To date, most of these attempts have been pathetic and are easily recognized, but that is likely to change in the future as criminals become more clever.
OS X viruses do not exist, but intentionally malicious or poorly written code, created by either nefarious or inept individuals, is nothing new.
Never install something without first knowing what it is, what it does, how it works, and how to get rid of it when you don’t want it any more.
If you elect to use "anti-virus" software, familiarize yourself with its limitations and potential to cause adverse effects, and apply the principle immediately preceding this one.
Most such utilities will only slow down and destabilize your Mac while they look for viruses that do not exist, conveying no benefit whatsoever - other than to make you "feel good" about security, when you should actually be exercising sound judgment, derived from accurate knowledge, based on verifiable facts.
Do install updates from Apple as they become available. No one knows more about Macs and how to protect them than the company that builds them.
Summary: Use common sense and caution when you use your Mac, just like you would in any social context. There is no product, utility, or magic talisman that can protect you from all the evils of mankind.