That system created Administrator account is a fall back, a safety net, in case anything happens to your own admin account. I'm not sure why you wanted to delete it.
You may be lucky. If there is a System Restore point for a date before you deleted that account, you can restore back to that date.
If not, I fear those documents are gone.
When normally you install win xp sp2 an account of administrator and guest account is created automatically and so it so happened that I created another administrator and then deleted the other administrator which was created by default and unfortunately there were documents that I had created which were important, but since then I have never been able to locate them,how do I recover those docemnts,help pliz