You're on a PC? You must be, what with the virusin', yes?
You should run Malewarebytes. It is AMAZING. If you can't actually download it on your computer (some viruses will make it close to impossible to reach anti-virus software on the web), download it on someone else's computer and move the installer to yours with a USB stick. Make sure you are not connected to the internet the first time you run it (you may have to run it more than once). After the first run through, it's probably safe to connect to the internet to update the virus database.
Another thing to do is to see what processes you have running and do a search on anything that seem suspicious. You can usually get a lot of good information about what each .exe is and, if it's malware or a virus, how to remove it.
<---IT department
You should run Malewarebytes. It is AMAZING. If you can't actually download it on your computer (some viruses will make it close to impossible to reach anti-virus software on the web), download it on someone else's computer and move the installer to yours with a USB stick. Make sure you are not connected to the internet the first time you run it (you may have to run it more than once). After the first run through, it's probably safe to connect to the internet to update the virus database.
Another thing to do is to see what processes you have running and do a search on anything that seem suspicious. You can usually get a lot of good information about what each .exe is and, if it's malware or a virus, how to remove it.