Endless objects with rectangle, ellipse and line tools. Please help!

[Guest]

When using the rectangle, ellipse and line tools, when I click and drag, instead of getting one object, I get endless objects. This have never happened before.  I have tried closing and restarting Illustrator, but it is still the same.  Please help!

[Ton Frederiks]

Is the ~ key stuck?

If not resetting Preferences may help.