query issues - critera being ignored

All,

Found some similar posts, but didn't help my sitaution. Any help would be
appreciated. I've got the following in query design view. The function
works and pulls in a variable from combo box. The appropriate records are
selected. What is killing me is if I add an "or" conditon. Either of the
conditions work seperately but when both exist in the query, all users
dispalyed is the outcome regardless if the variable is null or has value.
Trying to avoid wrtiing multiple queries for a form. Any thoughts? Thanks in
advance.

(WORKS)

STATUS USER
---------- --------
"COMPLETE" GetUSER("A")

(WORKS)

STATUS USER
---------- --------
"COMPLETE" Like "*" (or use a blank)


(DOES NOT WORK DISPLAYS ALL, ignores GetUSER)
---------- --------
"COMPLETE" GetUSER("A")
"COMPLETE" Like "*"