No, it's not time to call the vet, but if your computer is running like an overweight basset hound, it may be time to put a leash on some unwanted programs. These unwanted programs are classified depending on how they attach themselves to your computer.
Viruses are programs that attach themselves to other programs. They also replicate themselves and attempt to infect other systems.
Trojan Horses are programs that are embedded inside another program that appears to be something of value.
Worms are programs that try to replicate themselves and spread to other systems. Unlike viruses, however, they do not necessary infect other programs.
Malware is a generic term that refers to any “Malicious Software” particularly if that software is a virus, trojan horse, or worm.
Spyware are programs designed to track what you do on your computer and report that back to the author of the software.
Adware are programs designed to produce advertising typically while you are browsing the Internet.
PUPies are Potentially Unwanted Programs that are installed by the user. Typically, the user is tricked into installing these programs by vague license agreements or by accepting all of the default installation options when installing some other program. Spyware and Adware typically are classified as PUPies.
All of these programs should be removed from your system. Your first line of defense is simply being alert when opening emails or downloading a new piece of software. Once you get one of these programs on your computer, they tend to invite their friends over and have a party.
You need a good anti-virus program running at all times. AVG, AVAST, and Microsoft all make free anti-virus programs that are good. Keep in mind that nothing is 100%, especially when it comes to the programs that you actually agree (although unwittingly) to install.
You will also want a second program such as MalwareBytes AntiMalware that you will run once a month or whenever your computer starts to slow down. The free version of MalewareBytes AntiMalware does not run in the background, but runs only when you tell it to. This makes it play nice with other anti-virus programs. Often, if you have two or more anti-virus programs running at the same time, they will fight among themselves, making your computer run slower.
Although PUPies may be cute and playful when you first get them, it's not long before you are having to clean up the mess they leave on your rug.