Dedicated to the technically disadvantaged!

My guess is you are running W98 so that's an advantage because it only uses 64mb of memory where XP uses 128mb.
I would tell you to turn off traffic, water, shadows, aircraft reflection, turn down scenery to less than sparse use 800x600 and use the latest drivers for your video card.
You want to have some clouds for pure enjoyment so turn them down as far as possible and keep them at simple.
Your main objective is to turn off as many of the features as possible so that your aircraft after it leaves the "busy scenery" of an airport is to fly without stuttering, a slide show.
If you notice when you are in "settings" that if you pass your mouse pointer over a slide you get a message in the bottom left corner. Many times it will tell you that this turned up will effect performance, those are the ones you want to turn down or off.
Don't ever let someone discourage you from enjoying it because of the age of your machine.
If you can afford another memory chip no matter how much it will be of great help.
Enjoy!

To the Guest I would say the same thing and add that you are not alone. Many of us with the so-called 'hot rod' systems of 2 years or so ago are now finding that the speed of the 'game' is causing the stuttering that RadarMan mentioned.

I myself have downloaded the latest driver for Nividia and have plenty of memory to spare on this CPU but really do think that the only solution available to many of us right now is to turn down the effects as mentioned.

The scenery and everything else is a big part of the experience and enjoyment, but the focus on the skill of multi-tasking flying is the main object.

Happy Flying!