Malwarebytes.org and download malwarebytes they will give you a free trial that's what I use. Waiting until a lifetime for 1 PC goes on sale at newegg to buy a license for it. Works like a charm
I would suggest backing up all your local hard drive DATA and nuke the OS. It's not worth the time to scan with third party sw and have the malware come back in couple weeks or months.
Some of these malware are smart enough to lay low and not be detect at all. And at an certain date and time it will launch the attack. So, wiping the whole hd will be best solution, it's a pain to reinstall all your apps, but gives you a piece of mind that your pc clean and not infected.
Depending on what kind of virus it is you may need a root killer program also.
If you can google what it does to your PC there will prob be many answers to how to get rid of it and which root kits to get.
Does it redirect your google search everytime you use it?
If so use a different web browser to search for google redirect virus and there will be results for which root kit to download.
Anything you download scan with malwarebytes first.
Also having
Adblock+ on the web browser is a great way to defend against viruses and ads too but that's an added bonus it's also free or whatever you wish to donate and it works.
That is very wise.
Try googling your virus symptoms from another device.
Then when you have the necessary tools to get rid of the virus boot the computer into safe mode and run them.