How to avoid Malware
Malware in installs
In a lot of programs that you want to install they have hidden software in it that may or may not want to damage your computer or gain information.
A lot of this is down to the developers (Or sometimes distributors) needing more money, so they allow extra software to be bundled in. We do not want or need this software.
So, What so we do about this? Do we have to accept it? No.
There is an amazing piece of software called Unchecky which is a tiny download and install that runs a service in the background to monitor installations. It looks at them to see if there are any bundled extras that you may accidentally or intentionally be led to "accept". If you try to allow something it will try to inform you of your actions and check that you wish to continue.
No Computer is complete without Unchecky.
Download Unchecky Here
Malware in general
You will always come across malware throughout time in the world of computers, so you need to be ready when it happens. Don't let them in in the first place.
A good Firewall is your first line of defence, which is often forgotten about. It is literally like a wall, if you have no wall at all, anyone can stroll in. If there is a wall but it has big holes in it then someone might sneak in. But if your wall is solid and has an Antivirus looking at anything that comes in and out, it makes it much harder in comparison for malicious software.
There is a firewall built into Windows but it is generally better to get a commercial one, it doesn't have to be paid, there are some good free ones:
ZoneAlarm Free Firewall
Both Zonealarm and Comodo have paid versions of this software that contains deeper protection with added products.
Next that is needed is an antivirus software. That is the next line of defence. This should keep an eye on everything that comes and goes through the computer to make sure it has no signs of being a malicious piece of software. Most "antivirus" these days pick up more than just "virus", not as well as specialised tools as mentioned later, but they try.
As a note, Avast has been known to include the previously mentioned extra software and wants you to install things like a Google toolbar, so be careful what you click.
At this point, there are specialised software to help against different types of infection. For example:
Specific antimalware, antispyware, antikeyloggers, antirootkit. Then there are tools to try to accomplish different tasks such as Peerblock.
Peerblock is a tool that literally tries to block people out of your computer, it relies on lists of IP addresses and looks at anything going through the network and if it is on the list of blocked items it doesn't allow it to continue.
This is a more advanced tool but if you wish to try it a good place to get IP lists from is iBlocklist
Peerblock Download Here
As for antimalware there are a few good options:
Malwarebytes Antimalware Free
Spybot Search and Destroy
Trend Micro HiJackThis
Trend Micro HiJackThis is the only one that does not have a paid version and is more dangerous than the other two. It should only be used by someone who is really sure of what they are doing. Malwarebytes is the simplest to use out of this list.
As for antispyware, all three of the antimalware software listed above do well at removing spyware an alternative is SuperAntiSpyware
With antikeyloggers a good antikeylogger is KeyScrambler. They offer different version including a free one, but the higher the package, the more applications are protected.
QFX Software KeyScrambler
Rootkits can be a pain to remove because in order to work properly and not be found easily they really sink their teeth in. This can result in damaging the machine upon removal. So upon attempting a rootkit removal you much know what you are doing as the tools can be very powerful to have to deal with the rootkit.
Kaspersky TDSS Killer
GMER especially is a strong tool and is highly not recommended to use if you are unsure of what to do.
Even if you are downloading from a respectable website and trusted source, you must be careful as there has been lots of attention brought to Download.com as some of the downloads have been packaged with extra software with their own installers, this is where Unchecky comes to be priceless. Literally, its free, there is not many reasons not to have it.
There are some people who hijack a website and replace the downloads with their own, so it is important for make sure that the file you downloaded is the one the developer wished for you to get. This can be done through a checksum. This is a string that should be the same from the file as they provide. Any change to the file will make a change to the checksum. This tends to be an MD5 or SHA1 string.
There are a few pieces of software including one that will be hosted here made by TheTechSolved. There will be a link here when it is available. Until then VirusTotal as mentioned below will give you the checksum of a file if you scan it.
If you are unsure of the download, a good thing to go is use a service such as VirusTotal. By going to them you can point them at a link, download or file and have them scan with multiple virus engines to see if there is anything in it.
It is not a good idea to have more than one antivirus installed at one time because they can conflict with each other, but you can have antivirus installed along side antimalware and antispyware.
If you need a second opinion from your antivirus if you think it has given a false positive or has missed something then you can use a service such as Trend Micro Housecall.
Housecall is an antivirus that is an on-the-fly type, you download the file, check for updates to make sure it is current and then just scan.
Trend Micro Housecall