Its in the [help][1] - you contact stackexchange using the contact us link, and set your profile to "delete me". 

I'd add the problems you've had *might* be solved by reading through the help, since your other question and this were *both* off topic for SU proper


  [1]: http://meta.superuser.com/questions/691/how-do-you-delete-a-super-user-account