Monitor will not come on

        *Make sure that you plugged the IDE cable of HDD in correct position to both mainboard and HDD.
         *Unplug all devices including HDD. Just let mainboard+power supply+ram+cpu stay. Check if now you can see a screen.
         *Unplug Ram and check if there is a beep sound.
         *Release the CMOS battery and try powering on.
         *Reset your BIOS with its jumper.

Interesting, with the memory modules removed I expected to hear a shrill beep when I powered on and yet the P/C made no noise, also the monitor did not come on.  I have tried, so far, removing all the iede connections,  no luck.  The Hard Drive is a SATA and the cable connection looks okay, but even with it removed the monitor does not come on.  I have removed the battery and left it out for over 5 minutes, still no luck.  Any other ideas out there?

I think either you knocked a connector loose while installing the drive, or this drive itself is faulty and preventing the system from booting.  Follow MrHusy's instructions and see if it will boot without it.

You might also try removing the motherboard and running it outside the case, because it may be grounding on the case.

I have also put the old drive back into the machine and the monitor will still not come on.  How can you boot a P/C with no Hard Drive installed?

    No beep codes=
          1)No cpu available to opearte CMOS
          2)No mainboard to operate cpu and CMOS
          3)No Cmos
          4)Check mainboard speaker

    *Unplug all sata cords too. Do not forget unplugging powers of them too. Just let the mainboard powercord and the 4pin cpu power (if exist) plugged on mainboard.
     *Unplug CPU, then plug it again firmly.
     *Remove CMOS battery, turn its upside down (flip it) and plug it into its socket. Wait 10 seconds and the plug it into its slot in correct position (Do this step while AC cord is unplugged from power supply)

        We are trying to get the POST (power on self test) screen. And CPU+MOTHERBOAR+RAM+Power Supply are the necessary devices to get it or hear beep codes.

    Callendor is right. You might have dropped a screw somewhere while mounting your HDD with the excitement of having a new component :).

I have finished trying the latest steps and still no monitor.  I know this flat panel is good because it works on another machine.  All of the plugins appear to be connected on the Motherboard.  Any othre ideas?

         Is your PC powering on?
          Check if Reset button is not stucked?
         Just forget about the monitor, your current goal has to be able to hear beep codes. Check if little mainboar speaker is connected.
          Gently! press on chipsets with your fingers. Make sure that floppy,sata,ide,pci,ram,hdd,usb,keyboard,mouse both data and power cords are NOT connected. And keep staying like this along your workaround.
     

I didn't drop any screws and I'm really not excited about changing out a Hard Drive.  There is not any loose objects inside the case.

The P/C is powering on okay.

I can't find a speaker on this Motherboard.

    What model is your mainboard? "changed a Hard Drive in and when I rebooted it to load the HD " Changed HDD and then rebooted or powered on?  Was PC powered of during changing?
        Unplug the mainboard and powersupply from your case to make sure everything is unplugged. Seat mainboard on a dielectric surface and plug the power cord. Use a screw driver to contact the two pins (power pins that the cable coming from power button is pluuged to) for powering on. But be careful, do not touch other pins.
        Now we have only cpu mainboard and power supply(speaker should be integrated). Do you hear any sound?

The Motherboard is a K8VGA-M; ver. 1 and yes the P/C was powered off during the Hard Drive change over.

Just to be sure, you turned the power supply switch back on, if it has one?

Sounds like your motherboard is fried....!!!!!!!!!!!!!! Get a new motherboad.

Were you grounded while changing out the HDD? If not, you may have given your motherboard a static shock and fried it (a shock too small to feel could still do this, so you might not even know you did it.)

If the computer turns on (fans and such start up) then it's not your power supply that's bad.

If known good video cards won't work, it's not your video card that's bad.

Try taking the memory out and then turning it on, if you hear a beep, the motherboard should be okay.

If you don't hear a beep, make sure there's a speaker on the motherboard.

If you don't have a system speaker, you can buy one.  I found several by typing "PCI diagnostic card" into google.  Each one is slightly different in the way they work, but it can tell you if your motherboard is dead or not.  I would give it at least a 75% chance that this is a bad motherboard, and wouldn't bother spending the money on the card, but if you're really attached to this particular motherboard...

Try making a BIOS reset. It has to be a clear CMOS jumper near the CPU slot. See if thats working