Adobe flash player error popup "Install Plugin"??

You may have inadvertently installed adware. You can expect that to occur as a result of visiting lowbrow websites. You do not need to download or install anything to fix it.

For a description of how this may have occurred, how to avoid it in the future, and for Apple's recommended actions read How to install adware. Apple's instructions are linked in the Recovery Procedure near the end of that document. Read and follow them carefully. Pay particular attention to the easily overlooked passages directing you to restart your Mac when required.

Although those instructions are designed for Safari you may be able to adapt them to Google Chrome. If you are unsuccessful or unable to do so, use Safari and determine whether the popups subside.

Review your Gatekeeper settings: OS X : About Gatekeeper - Apple Support. Gatekeeper is designed to help prevent you from inadvertently installing garbage software.

Please don't call in just any computer help guy, when you can call Apple who will fix anything that's wrong for an out of warranty cost of $29 US. Many generic "computer techs" treat Macs the same way do PCs, assume they can be afflicted with the same problems, and that usually leads to misery.

Apple's instructions can seem daunting but they really are not. They are lengthy, but designed for anyone to follow without the need to use any third party, proprietary, or copyrighted material. Follow them with care, and there is anything at all unclear about them, just ask.

why do the popups only occur when I'm trying to get on MSNBC ...

I have no idea. I wouldn't allow that site to load on anything I cared about. Adware can affect different sites and different browsers in different ways. Consider using Safari or Firefox instead of Chrome, and determine if you can find any differences between them. I wouldn't trust Chrome either – Google products are specifically developed to exploit you for their benefit, not yours.

However, I'm assuming this does not apply to a "house call" repair, and that I'd have to take my computer to them.

I do not believe that will be necessary for the problems you describe. Just remember to contact Apple using the Contact Us link below – never by following a link from the results of a Google search.