0001193125-07-223446 15-12G 1 20071023 20071023 20071023 CDW CORP 0000899171 5961 363310735 IL 1231 15-12G 34 000-21796 071184715 200 N MILWAUKEE AVE VERNON HILLS IL 60061 8474656000 200 N MILWAUKEE AVE VERNON HILLS IL 60061 CDW COMPUTER CENTERS INC 19930322 15-12G 1 d1512g.htm FORM 15