Annoying Double Underlined Words

[grandpajoe]

Lots of 'em have appeared all over the place. Please tell me how to get rid of them!!

[bednobs]

you have some sort of advertising malware

[Old_Geezer]

Download, install, and run malwarebytes.
Consider doing so with superantispyware also.
Never hurts to run your AV on a scan also.

[Buenchico]

As has been indicated above, it's a malware attack.

In the vast majority of cases simply running the free version of Malwarebytes fixes the problem:
https://www.malwarebytes.org/antimalware/
NB: When installing it take care to deselect the pre-ticked option to take a free trial of the Premium version. When malware is found use the 'quarantine' option to zap it all.