Cannot boot operating system

I have a Dell Dimension 5100. OS is (supposed to be) Windows XP w/ service pack 1a. Service tag DKW2B81. Bios version A01 (05/25/05). Processor Intel P4 CPU 2.80Ghz. Numbers visible on motherboard are DS/N CN-OJ8885-69861-57J-1422 C/O CN. After running self diagnostics on just about everything including the hard drive, internal memory and timing. Under the Symptom Tree, Cannot Boot the OS, System Timer-Timer Functionality Test, the following error code is displayed: 4C00:041C. Msg: “Channel 2 is not operating correctly. No periodic ticks were generated. Realtime clock is probably not functioning.” Express Test yields same results. I have tried to re-boot via CD, system receovery F-11 (Dell specific?), re-seating internal memories, hard drive, bios battery (did not replace yet) and removing the cable internet modem. Cannot boot in any safe mode nor restore to last known configuration. Upon restart, the following screens are observed: Dell logo screen with F2 or F12 options. When trying to reload windows via the original CD that came with the computer, “windows setup” appears in the upper left of the display, windows appears to be reloading, then “setup is starting windows” appears in the lower left of the display. It hangs there. Tried contacting Dell to no avail. Any suggestions?