Mile-O-Phile has it right on the money. In your query, you need to create a new field and add one of the (or combination of) the functions he listed.
Say you have a field FName, but when you import the data it looks like 123Jeremie, 321Bob, 409Janet. You just want the name itself and not the numbers. Use the query builder and add the tbl that contains the data. In the top row of the column you would add this (under the assumption the field name is FName and the new filed you create is called RegName)
RegName: Right([FName],(Len([FName])-3))
You could easily create this function by using the BUILD option and making the selections from the built in functions. What this string is doing is...
RegName: - creating the new field within the query
Right ( - telling it to return everything within a certain range starting from the right.
[FName], - this is the filed you want to look in
(Len([FName]) - returns the total number of characters in the field.
-3 - subtracts 3 from the total number of characters.