If 10 people reply, you will get 10 different answers. First - use what you have on hand to start with. That is, make sure Windows Firewall and Windows Defender are running, to cover immediate firewall and spyware concerns. Then you need an anti-virus program. There are several excellent antivirus programs to chose from, some free, some not. I recommend you chose one that performs consistently well in tests by the following respected labs:
Be sure to use the "custom" install options when installing these and uncheck any options for extra programs toolbars, or add-ons that you do not want.
I also recommend
Malwarebytes's Anti-Malware (MBAM) for supplemental, on-demand scanning.
The AV information above is extracted from my
Practicing Safe Computing sticky. You might want to scan through it for more information.
