arduino will not run

When I click on arduino.exe I get the message "Arduino can not run because it could not create a folder to store your sketchbook. I've looked at this in previous posts but can not figure it out. I have windows vista. Capricorn

Maybe you already ran arduino as administrator, and it created a sketchbook directory in your home directory. If this is the case you can either delete the existing directory (should be empty) or continue running arduino as administrator. You can also look for the file preferences.txt (somewhere within your home directory, not the one in the arduino program directory) and see/change the property named sketchbook.path.

Thank you for response.

It may be that I ran it once another way, I downloaded it more than once to different locations then got rid of one of them. What might be the name of the directory that would be deleted? My user account type is administrator so that doesn't seem to matter. I do find preferences.txt (in appdata/roaming) but there is no mention of sketchbook in the text of that file. (there is line: last.sketch.count=0)

What might be the name of the directory that would be deleted?

The folder should be "Arduino" in Documents and Settings\user\Documents. But if it's not in preferences.txt it is probably nowhere.

You may try setting it yourself in preferences.txt:

sketchbook.path=C:\Documents and Settings\user\Documents\Arduino

so that it tries to start from there instead of some other, maybe non-existent, location.
Then you may also delete preferences.txt -- it will be created the next time the program is run.

You can get more information by running arduino from its own program directory, using the command prompt with a debug option:

arduino.exe --l4j-debug

This should create a launch4j.log file with details about the attempt.

Thank you Spatula. I have it now. I put the line in preferenses.txt, with a slightly different path.