My hp pavalion dv2500 does not boot. When I turn power on, screen is blank, I hear 4 beeps, power lights flash,fan is on....computer just hangs in that state. Seems to be frozen. Does not boot pass this stage. It will not allow me to do a darn thing! Help! Computer is less than ayear old.....I do not have a back up disk to boot from. Windows Vista, Internet explorer 7 AMD . thank you

There are a ton of possible reasons. Some easy troubleshooting steps:
1) Check the power cable. If you can borrow a different power supply, try that.
2) Remove the battery and try it.
3) Hold down the power button for 20 seconds or so.

Beyond that, tell us everything you're seeing and hearing when you try to boot.
1) What indicator lights does your computer have? Which ones light up when you're trying to boot?
2) Is there any change in the screen when you boot. Does it go from a deep "off" black to that slightly lighter "on-but-blank" black?
3) Do you hear any noises? Beeps? Fans? The chatter of a hard disk? The whirr of the CD drive?
4) Does anything appear on the screen? Tell us about any messages that flash up.

1. When you press the power button to turn it on, do you see any thing on screen, like the toshiba boot up screen or something like that. Or is it completely blank (black color) always.

2. Can you see a faint image of your desktop (try to see it in dark place with flash light). This is important to confirm.

3. Also, when you press power button, do you see the LED lights on laptop blinking or solid green (which ones are in blinking/solid) and do hear any sound ? Or do you feel that your laptop doesnt even try to boot.

4. Can you hear any Beeps when you try to turn on the computer. If yes, what is the sequence of those beeps.

Continued......
If you answers are -
1. blank
2. no image
3. only the satellite light is blue, the powercord is blue and the battery is blue
4. no noise

Please do the following carefully and let me know result :
1. Shutdown and Unplug your laptop.
2. Remove the battery from the laptop.
3. Wait 2-3 minutes
4. Now press ON (power button on laptop) for 1 minute
5. Then release the finger and wait one more minute.
6. Now plug in the power cable (dont insert battery yet) and press ON button.
7. Did your screen start working now ? (do you see windows loading)

Did it boot all the way? Do you hear the fan running, disk drive spinning? If it sounds like it booted but the display is black, try this:
When you press the power button do you hear fansrunning, hard drive spinning, lights on the computer, hear any beeps or lightsconstantly blinking, hear the DvD/CD drive click and the light on the drawer ofthe DvD/CD turn on for a second or two? If so the laptop is trying toboot or may have booted, but the screen is not showing for some reason.

Beep tones and blinking lights tells the technicians what is going on with thelaptop and why it is not booting. Most times it's a motherboard issuewhen you hear beeps or blinking lights continuous.

Do you hear the fans running? Do you hear the hard drive spinning? Did anything ever appear on the monitor?

Remove the Power Cord, Open the Case and remove one of thememory chips. Set the chip aside then try rebooting the computer. If it boots, then you know the memory chip you set aside is bad so mark an x onit with an ink pen. If it fails to boot then move the chip to the nextmemory slot and try rebooting. If it fails take the chip out and set itaside, then put the other chip in and try booting it in both slots. If itboots, just to verify that the chip set aside is bad, mark an x on it and putit into the open memory chip slot and try booting.

Replace the fan or your computer will run hot and keep turning off.

Or are you saying this is what happens when you power on the computer? if so: When you press the power button do you hear fansrunning, hard drive spinning, lights on the computer, hear any beeps or lightsconstantly blinking, hear the DvD/CD drive click and the light on the drawer ofthe DvD/CD turn on for a second or two? If so the laptop is trying toboot or may have booted, but the screen is not showing for some reason.

Beep tones and blinking lights tells the technicians what is going on with thelaptop and why it is not booting. Most times it's a motherboard issuewhen you hear beeps or blinking lights continuous.

Disconnect the drive and try to boot to the BIOS (usually with F1, F2 or Delete key). If that doesn't work, try removing all cards from the computer (except a video card if the video port is not on the motherboard). If you can boot this way, try inserting back any removed cards to see what hangs it. Do you hear any beeps when the computer is booting (beep codes)?

there is a lot of factor for a death pc. ignore it all. just check the following :
1. is the hdd led flashing
2. remove the cpu cab and make sure that the fans are spining for both smps and processor
3. any un usual beeps at startup
4. any onscreen message or a blank screen
5. and bla bla ... ...
so far, let's fix it
1. check power and signal connectors of hdd or replace new .
2. re connect all the power connectors on the mobo or change a new smps
3. de assemble, clean and re assemble all the parts inside if there is any unusual beeps
good luck

The first issue you had with one long beeps and two short beeps is a memory module error. see the following HP website:
http://h10025.www1.hp.com/ewfrf/wc/document?docname=c01732674&cc=us&lc=en&dlc=en&product=1842155 I would replace the memory chips and try again. If you have more than one chip try booting with one at a time to discover that one of them may be bad.

The beep patterns always tell you what the problem is, but it depends on what kind of BIOS is in your computer. You can take a look here, maybe you find what is the problem with your machine: http://www.pchell.com/hardware/beepcodes.shtml