Believe it or not, most W9X crashes are related to video issues.
The first thing I do for a system is to update the drivers.
Start with the drivers for the motherboard.
Then, DirectX (from Microsoft)
Finish with the video card driver and monitor driver.
Now, a PII 266 is around 4 years old.
Over that period of time, Windows can build up enough bad links and excess bagagge in the registry that crashes are unavoidable.
The BEST way to correct this, is to;
back up your files and settings,
format the hard drive,
re-install Windows from scratch.
You will be amassed at how much faster and better your system performs.
As an alternative, you can bring back most of the stability, and some of the speed with a good registry cleaner.
I have used both Norton WinDoctor and On-Track Fix-It (now V-Com http://www.v-com.com/)
Chas