After changing the ram in tower when switch onpc starts with 3 long beepsdoesnt shut off it stays on but gettin nithing through to monitor"? Tried new n old ram which both work on diff" pc"? What does 3 long beeps mean"? Please help.

have you tryed starting up in safe mode to see if you can get into your windows?

Generally 3 long beeps indicates a memeory problem cant tell you for sure without knowing exactly what bios the computer is using. have a look here.
http://www.pchell.com/hardware/beepcodes.shtml

Make sure you have the cable that plugs into the back of the computer from the monitor screwed in tight. Also make sure the cable on the back of the monitor is screwed in tight and also that the power cord on the back of the monitor is pushed in all the way.

I'm almost certain you're not in standby mode. Does the computer stay on when you get the no signal message? Do you hear the fan blowing, do you hear the disk drive spinning? If not, I think your system has completely shut down. I'm thinking maybe a virus or some hardware/software conflict is stopping it from completing the boot cycle.

Try getting into the Bios or System Setup to see if the LCD Stays on and the computer stays on. Turn the computer off, then hit the power button to turn it back on. Look at the lcd screen and it will tell you what key to hit to go into the Bios or System Setup. Go into it and let the computer sit for 10 minutes or so to see if it shuts itself off.

If you are successful with the computer staying in the Bios or System Setup lets try getting into Safe Mode and see what happens. Turn the computer off and hit the power button to turn it back on and immediately start hitting the F8 key repeatedly until you see the SAFE MODE option. Select the Safe Mode option and let the system boot up. Safe mode will look different to you. The icons will be bigger and the lcd screen darker, but that's normal. If you are able to see the desktop in safe mode just try opening up MS Word and maybe let it sit for a few minutes to see if it shuts off.

If safe mode was successful, then try booting it normally. If it fails, we know we've got an issue.

Change the internal Ram sticks. This can cause a "Hold" in the BIOS boot process, thereby stopping the machine from going to the Operating System. Hope this helps.

1. Check the connections and make sure they are still tight. If the monitor isn't getting data signal it can go into power saving mode. Since it was working I would check this first.

2. Look in control panel under POWER OPTIONS and make sure it's not set to turn off after so long.

3. Also check the settings for your screensaver under display settings. That too could put it into poewr saver mode.

It could be a setting on the monitor itself that somehow got changed. Check out the settings to see if anything has changed.

Could be RAM memory, Video/Graphic card, HD, power supply - your description is not that clear.But at least you know where to start.Can you hear fan working,or are there any lights on your power supply?Can you hear Hard drive starting?Open the tower and check memory modules - take out one at the time and try-sometimes changing their places will do. Good luck, and keep us posted.

A solid amber power LED on a Dell System is indicative of a no post. There are 4 diagnostics LEDs on most Dell Towers (Either on the back marked ABCD, or on the front marked 1234) they can give more details of what the POST problem is.
Troubleshooting: Disconnect all external connections to tower except power, turn it on, see if the LED indications changed. If they change, then connect disconnected items one at a time till the failed item is found. If no change, the open tower, remove all PCI expansion cards, see if system will boot. If still no change, then most likely a motherboard failure. Take RAM out, see if you get a Beep error code when powered on, if no beeps, replace motherboard. If it does beep, try RAM modules one at a time, if it boots with 1 but not the other, replace the effected module. If no boot, with either replace MB

please your monitor's switch is currently ok and warking?
second time your open the cpu couver and so the all add a smps sowaked in the motherboard add is ok. and you so the smos power
is down power you changed smos power and restart the pc and chack the ok.

First open cpu cabinet then REFIX RAM memory.
Pull cmos cell for 10 minutes then all settings are defaults.
.
Then reconnect vga cable from your monitor to cpu vga port.
Then when you power up press continue F8 key so you can see safe mode and other menu then enter in enable vga mode then go to control panel then dispaly property then settings then change screen resolution to 1024*768 then apply and ok.
Then restart and check .

if ur monitor is not coming up... check uplugging the monitor cable from the tower.... if u receive a msg on screen "No input signal" or "No VGA Signal" then Monitor is working fine... if not received monitor is not working properly.

if Monitor working... open the tower and remove memory (RAM) and switch on the pc... u should get beep codes.. if u dint get it.... Motherboard gone bad....else... try inserting RAM in other slot... even then its not lighting up...RAM problem or RAM solt problem..