Dell OptiPlex 755 User's Guide - Page 351

Code 3-4-2 3-4-3 4-2-1 4-2-2 4-2-3 4-2-4 4-3-1 4-3-3 4-3-4 4-4-1 4-4-2 4-4-3 4-4-4 Cause Screen retrace failure Search for video ROM failure No timer tick Shutdown failure Gate A20 failure Unexpected interrupt in protected mode Memory failure above address 0FFFFh Timer-chip counter 2 failure Time-of-day clock stopped Serial or parallel port test failure Failure to decompress code to shadowed memory Math-coprocessor test failure Cache test failure System Messages NOTE: If the message you received is not listed in the table, see the documentation for either the operating system or the program that was running when the message appeared. Message 8042 Gate-A20 error Address Line Short! C: Drive Error C: Drive Failure Cache Memory Bad, Do Not Enable Cache Possible Cause The keyboard controller failed its test. An error in the address decoding circuitry in the memory has occurred. The hard drive is not working or is not configured correctly. The cache memory is not operating. Corrective Action If you receive this message after you make changes in the system setup program, enter the system setup program and restore the original value(s). Reseat the memory modules (see "Memory" on page 313). Ensure that the hard drive is installed correctly in the computer (see the "Drives" section for your computer) and defined correctly in the system setup program (see "System Setup" on page 280). See "Contacting Dell" on page 370 for instructions on obtaining technical assistance. Solving Problems 351