Unfortunately, I’d have to agree with @John_Betong that there’s no quick and easy solution here.
Frames have been dropped from the latest version of HTML. Although desktop browsers will continue to display them OK, they are not considered a good choice from an accessibility point of view.
You could do away with the frames, and add the menu to each page using a PHP include. That’s not difficult, and we can walk you through it, if required.
Where you are using HTML tables for layout, you should try to replace them with more semantic elements, or even
<div>s. HTML tables used this way will not readily resize to fit on small screens. Use CSS to control the layout (and all other styling, too). There is always more than one way of achieving a layout with CSS, but you might find it simplest to try CSS display:table and related properties.
The key to making a site flexible, so that it will adjust to different screen sizes, is to avoid fixed widths as far as possible. Use flexible measurements like em or % to define the size of containers, where needed. That will get you off to a good start.
There is more to it than that, but if you can get that far, it will be much easier for us to help you put the finishing touches to it.
These articles might help give you an insight into responsive design.
It seems like a lot to learn at first, but it’s actually easier than you might think. Just take it one step at a time, and ask for help when you need it.