If endless typing has you worried about the health of your wrists, remember that continual mouse-clicking can cause just as much damage.
In Windows 98 you can eliminate double-clicking by opening Explorer, selecting View-Folder Options, selecting the Custom button, and clicking Settings.
Then change the setting in the 'Click items as follows' box from 'Double-click to open an item' to 'Single-click'.
In Windows 95 install and customise the latest mouse driver from your mouse's manufacturer.