You need a layered defense. this is how I do it.
First of all, I have ALL my internet marketing stuff on an external hard drive so I can unplug it when I clean the computer.
Download Cleanup! (WITH an exclamation mark) and install it and run it.
(cleans out the junk and recovers wasted disk space)
Download MalwareByes Antimalware free edition, load it and and update it, and run it.
Down load Spybot search and destroy, there are fakes, so get it from safernetworking , org. Install it and update it, and run it.
These two tools will keep the adware and spyware at bay. Make sure you do not scan your IM drive with these tools. In the event you do both of these programs allow you to select the items to remove, so always check the list to see if a tool has been identified. If it is coming from your IM drive or directory, just tell the programs to leave it alone.
For anti-virus protection, I use avast free and just put up with the nag screen that pops up every so often trying to get me to buy it.
The best way to use anti-virus software in "Our" case is to leave it turned off, and only turn it on to scan for problems. Left to its own devices antivirus software will scan every file you touch for viruses, and prevent the their execution, quarantine them, or outright delete them automatically.
This means everything you download and upload, which will kill half the tools you use on a regular basis.
What you should do is turn the antivirus off and leave it off. Turn it in to scan your new downloads, then turn it back off.
Then what I do is this.
I create two folders, one called "downloads" and one called "DT Downloads". DT stands for "Drug Test"
Anything I download from a reputable source, or a commercial product Goes into the "Downloads" folder. I am not worried about those being infected.
Anything I download from any ...Ahem... "questionable" site goes into the "DT Downloads" folder. At the end of any download session, I right click on the DT Downloads folder and scan it with the three tools I have mentioned. Should I want to use a download immediately, I just right click and scan the item first.
You should also download a little tool called "RKILL" from systernals and save it to your desktop. This little gem will kill any and all Rouge processes running on your machine immediately upon execution. Trust me when I say this, you run this program and ALL the bad stuff will immediately die. Very handy to have on the desktop for those times when something pops and tries to take over your machine. Run rkill,l and get the hell out of there.
Remember that any malware can reside on your computer without infecting your computer. The program can sit on your computer's disk drive without harm, and only infect the computer's operating system when executed. This is why your "tools" will set off your anti-virus. The tool behaves in a way that a normal program does not, an the antivirus program naturally decides that you are up to something. Which of course you are.
If your computer is already infected I have a cheesy computer repair adsense site that has a cleanout procedure here to teach you how to clean out your computer with free tools.
I cannot post links so if you are interested in this procedure, IM me and I will send you the link.
Use this procedure to clean out your computer, but do not use the e-scan program. It automatically deletes everything it finds, and it finds a lot. It is great for home users to use, but people like us need to avoid it. Use the avast antivirus or AVG instead.
No offense intended by the "People like us" remark.