Every week someone walks into my shop in Somerville and says the same thing: "It's just been acting weird." They can't always put their finger on it — but their gut is usually right. Computers don't get weird for no reason, and malware is one of the most common reasons.
After cleaning infected machines here since 2011, these are the ten signs of a malware infection I see most often — the same symptoms that show up on my bench week after week. You don't need all ten — two or three together is enough reason to get the machine checked.
Malware runs in the background and eats your computer's resources. If your machine went from fine to sluggish in a matter of days, and the fan is roaring even when you're barely doing anything, something is working hard behind the scenes. Sometimes that's a hidden program using your computer to make money for someone else, around the clock.
A pop-up on a sketchy website is one thing. Pop-ups appearing while you're just working — or when the browser isn't even open — mean unwanted software is already installed. And here's the part most people don't know: pop-ups rarely travel alone. The infection showing you ads is very often bundled with others you can't see. Whatever you do, don't click them.
New homepage you didn't choose. A search engine you've never heard of. Toolbars and extensions you never installed. Searches that redirect somewhere else. That's a browser hijacker, and it's one of the most common infections we remove — on Windows PCs and Macs.
This one's a five-alarm signal. One of the first things modern malware does is disable your security software so it can work uninterrupted. If your protection is off and won't turn back on, the malware is already in — and it's winning.
Malicious software forces your system to do things it was never designed to do, and the system responds by freezing or crashing. A blue screen once in a blue moon happens. Crashes becoming a routine is a symptom — of malware, or sometimes a failing drive. Either way, it needs a diagnosis, not a shrug.
Take a look at your desktop and your list of installed programs. Software you never chose — "cleaners," "optimizers," random games, mystery toolbars — usually rode in bundled with something else you downloaded. Some of it is merely junk. Some of it is spying on you.
If your hard drive is mysteriously filling up and you haven't added anything, bloated unwanted software may be squatting on your drive. Malware isn't tidy — it doesn't ask permission for the space it takes.
Many infections "phone home" — they connect to a control server to send out your information or pull down additional malicious software. If your network activity light is going crazy while the computer sits idle, ask yourself who it's talking to.
If friends or coworkers ask about an email or message "you" sent that you never wrote, take it seriously. Either your account is compromised or malware on your machine is using your identity to spread itself to people who trust you.
Real security warnings don't come with a phone number, and Microsoft and Apple will never cold-call you. Scary full-screen alerts with a "support" number are a scam designed to get remote access to your machine or your credit card. Don't call, don't click, don't let anyone remote in. I wrote a full breakdown here: fake virus warning pop-ups and how to shut them down.
Here's my honest take: a slow computer might be malware, or it might be a dying hard drive. Crashes might be an infection, or failing RAM. That's exactly why we diagnose before we touch anything. If it turns out your problem isn't a virus, I'll tell you what it actually is and what your options are. And keep in mind the opposite is also true — some of the nastiest infections show no symptoms at all while they quietly collect your passwords. "It seems fine" isn't the same as "it's clean."
People search for "virus symptoms" and "malware symptoms" like they're two different lists, but on the bench they're the same checklist. A virus is just one type of malware, so the symptoms of a malware infection — the slowdown, the pop-ups, the hijacked browser, the disabled antivirus — apply whether the culprit is technically a virus, a trojan, spyware, or adware. What matters isn't naming the infection; it's catching the symptoms early and getting it off the machine before it digs in. That's exactly what my virus removal service is built for.
Stop using the computer for banking, shopping, and email password changes. If there's a specific pop-up or warning on screen, take a photo of it with your phone — that helps me identify the infection faster. Then power the machine down and bring it in. The longer an infection sits, the deeper it digs in and the more damage it does.
At Dave's Computers, virus and malware removal in New Jersey is a $149 flat rate, with a $75 diagnostic that's credited toward the repair. I'll tell you what I found, how it likely got in, and how to avoid a repeat — in plain English.
Getting here is easy: we're at 75 North Bridge Street in downtown Somerville, behind Bank of America — a few minutes off Routes 206, 202, 22, and 28. No appointment needed: Monday–Friday 10am–5pm, Saturday 9am–2pm. Drop-off only. Call (908) 428-9558 with any questions.
First-time customer? Mention code VIRUS20 at drop-off for $20 off your virus removal.
Related reading: How to Tell If Your Computer Has a Virus · Will a Factory Reset Remove a Virus?