The "profile" in Mac OS X is in fact made up of the configuration documents in the user's Library folder. You can start by looking in the ~/Library/Preferences folder and deleting any that seem to relate to the program that keeps crashing. Also, delete these from the ~/Library/Application Support folder.
Still not fixed, you can delete all the stuff in the Preferences folder. This will reset every app to its defaults.
If that doesn't work, you can re-create the user. Simply:
- Make a new user from Accounts in System Preferences. (you've already done this)
- Make sure the new user has administrator privileges.
- Log in as the new user.
- Go into System Preferences - Accounts again and delete the old user. This can be a little slow on some older machines as it automatically archives that user's home directory. (about 3 mins for my iBook 500) Remember, this will archive and remove all the user
- Now, go into the /Users folder to find the archive for the deleted user. Rename it and/or move it to somewhere safe.
- Now, recreate the old user account. Just add a new user with the same name and shortname you wanted to use.