Out of Memory?

[Bridgebuster]

I'm new to the forums, and to Macs for that matter, so I hope this makes sense. I have a pretty recently purchased iMac 27" 5K with 8 gb of RAM. I was really pleased with the speed of this thing until just recently I started getting the "beach ball" and the whole system would just sit there. Most times I can't even Force Quit any apps and I sometimes get a message about the apps running out of application memory. This is with only Mail and Chrome running.
My son knows more about all this than I do and he said there is some kind of reset or something that can clear this condition. I don't want to lose any apps, data or setup. How can I fix this and get my speed back?

 

[honestone]

You possibly might have a virus on your machine. Do you happen to have either MacKeeper (real, real bad software), or CleanMyMac?

You should download, install, and run Malwarebytes Anti-Malware. You can get it from here:

https://www.malwarebytes.org/mwb-download/

 

[Bridgebuster]

You possibly might have a virus on your machine. Do you happen to have either MacKeeper (real, real bad software), or CleanMyMac?

You should download, install, and run Malwarebytes Anti-Malware. You can get it from here:

https://www.malwarebytes.org/mwb-download/

Thanks for the response. No, don't have either of those. I'll try the Malware killer you suggest.