A yellow monitor light indicates the monitor is NOT powered up, it is in standby waiting for the PC to tell it to turn on. I don't think your RAM is faulty. First try manually turning the monitor off. Power down your PC. Then turn the monitor back on. Then boot up your PC. Tell us what happens.

Hi,
I have done this several times. When I move the mouse or press a keyborad key, a message briefly comes up on the screen saying that it is in save mode (or maybe standby I can't remember for sure..I am at work). The screen goes back ti black very quickly. I tried to F8 or F8 when powering up the hard drive with no luck. Any other tips...? M

What made you think the RAM modules were bad? How did you determine that?

What operating system are you using?

When you installed the 2nd HD, and got it working, did you stay on the PC and do other things (check mail, surf, play games, etc.)?

When you left the computer, did you do a shut down, or just leave it on with a screen saver?

What type and model of monitor are you using?

From your last post, it sounds like you can boot up the PC without getting any error messages displayed. Is this correct? Could the message on the screen that you mentioned be "safe mode" indicating the operating system is booted up in the safe mode?

Have you tried taking the 2nd HD you put in, out and returning the PC to it's original configuration before the problems started?

The fact that the monitor says that its in standby/power saver mode means
-->it is in those modes
-->it isn't receiving a signal

Now as you've checked that the computer is on (are the LEDs glowing and fans spinning?) and yet you get the message, your problem lies somewhere in the CPU. Fisrtly, do you hear any beeps when you power up the computer? You should hear a single short beep. This means the POST was successful. No beep or many beeps (short and long) indicate either a loose connection or a hardware malfunction. Try starting your computer after disconnecting the new hard drive. You said that you checked your RAM sticks in another machine. Try getting that machine's RAM in your computer and see if your computer powers up. If it does, your RAM sticks are the culprit. If not, check for loose connectors on the hard drives, the optical drives, the power plug going to the motherboard. Also, ensure you have seated the RAM modules tightly. To be sure, once the RAM modules are seated tightly, you can barely see the gold connectors. Also ensure the locks on the RAM slot are in place when you install the RAM.

Hi,
On the back of the tower the diagnostic codes inferred that there was a memory issue. I also tried these mosules in my other computer, which gave me the same black screen and the yellow power light (instead of green). I am using Windows XP. After I installed the HD, I stayed on the computer for awhile, reading my e-mail and I think I played a game. I then logged off, but left my machine on. My monitor is a Dell flat screen (non-digital), sorry I don't have the specific number, I am not at home. When I turn the computer on it doesn't sound like it's booting internally and there are no beeps. The monitor screen does not change, it stays black. If I move the mouse the message "monitor in safe mode...press any key to continue" comes up for just a second and then goes away. If I press a key nothing happens.

I appreciate your thoughts! Thanks, Michele

OK. If the PC is a Dell as your monitor suggests, then you probably have 4 LED's on the back of the processor cabinet. (In my Dell, if A & B are yellow, and C & D are green, then it says the "memory failed to be sized or enabled". The corrective action is to reseat the memory sticks. For Dell PC's there is also a table of "Beep Codes", however, you say you hear no beeps, so I won't go there.

If the diagnostic LED's still suggest that you have a memory fault, then you really need to remove and reseat the memory sticks. When you replace them, carefully position them in the slot with the keyways (notches) in the correct orientation, and with two hands (fingers or thumbs, depending on the room to manuver), firmly press them into place until you hear them snap into place and the locks repositon themselves to the vertical position. Do one stick at a time starting on the inside and working out.

Then reboot. If you still have the same diagnostic LED's, then do like goldeagle2005 suggests and use memory from another PC. Let us know the results.

Hi
I tried using the RAM from my other pc with the same result. The diagnostic light codes on the back are the same. It doesn't sound like it's booting up. I tried booting it up with none of the RAM modules in the and it gave me 2 beeps. What do you think?

You would have got an instruction manual with your computer. Can you see what the diagnostic light codes mean? See the code in the rear and compare it to the diagnostic table given in the manual.

Otherwise, I suspect a loose connection. Check to make sure you've tightly plugged in all the cables. Also, ensure all peripherals (LAN card, graphics card, modem etc) are all snugly seated in their slots.

Have you tried reading the My PC won't start - Read this first! thread? In that thread, Catweazle gives a very detailed sequence of steps to take your machine through to try to diagnose the problem component.