Userform auto-fill if person already exists

[JeremySun]

I am using a userform in a workbook with approximately 5 worksheets. The user, puts there information into the userform and then presses submit and the information is put in the appropriate worksheet. What I would like to do is if the user has already filled out the form once their information fills in automatically. The input boxes are: First name ; Last name ; Class; Phone Number; Address. When they hit submit depending on what class they selected depends on what sheet it went to ie. English, math, Social Studies and so on. The information is put in rows the same way they enter the information so First name will go into A2, Last Name B2, and Class C2 .... Any help would be appreciated. Thank you in advance.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>