2 short beeps pause 3 short beeps

SOURCE: my lenovo n200 does on turn on it beeps and screen remains blank

Hi, you must remove both memories and return to wear them in the socket, it is for it that your equipment not power on correctly

SOURCE: Beep Codes for Troubleshooting HP Pavilion ze4125

remove and clean your RAM cards. use some contact cleaner with cotton wool to clean it. reinstall and try it. 

SOURCE: upon boot up, screen remains black,disk power up briefly

HOW TO FIX YOUR DV6000/DV9000/DV2000/tx1000/tx2000
All the Problems described are Graphics Related..

Faulty Nvidia Chip..Both Intel And AMD Based Motherboards..Though More Common on the AMD..
The symptoms of the Laptop Powering on and Shutting Off Repeatedly..Or.. Powering On and Having No Video...Or... Power Strip Lights Up, Beeps,Shuts Down...Or..No Power At All...Or.. Intermittant Loss Of Wireless/Video Goes In And Out/Touchpad Slows and Freezes..
To Fix this issue, You will need to Reflow The Graphics Chip.
I will Explain In Full Detail As To The Correct Method Below....
HP DV6000/DV2000/DV9000 Compaq v2000 Video Chip Reflow Instructions
First Step Is Complete Disassembly Of All Parts And Components..
Remove RAM, Remove CPU, Of Course Remove Heatsink and Fan assembly.
Next Step is Insulating the Motherboard... You need to Protect The CPU area, The RAM area, Cover any plastic Plug ports.
Try to leave 1/4 inch area around the edge of the chip free of insulation.
To Insulate the Board.. I use thick pieces of Tin/Aluminum, you can fold up some aluminum foil (tin foil) About 4 folds thickness....
Now that you have your Motherboard Insulated... Make Sure There's Nothing Flamable Or Burnable Below the Motherboard... it will get quite hot underneath.
You will need a Heat Gun.. You can get one of these at your Local Home Improvement Store, they cost about $15 - $30.. You Will Use ONLY the LOW Heat Setting... I REPEAT..... USE ONLY THE LOW HEAT SETTING ....
Next You Will Need Some Coins.. Yes Coins..
8 Quarters and 2 Nickels... Put the 2 Nickels On the Bottom and Stack Quarters On Top...
Place The Stack Of 2 Nickels And 8 Quarters On Top Of The Graphics Chip...
The Reason for using the Coins: Using the coins serves a few purposes...
1) It Helps Transfers the heat Into The Chip More Evenly/Slowly
2) It Helps Hold The Heat Longer/Then Helps To Cool Slower
3) It Gives The Correct Amount Of Weight That Is Needed To Press The Chip

A Thing To Look Out For...
Hewlett Packard is nutorious for using the RED epoxy around the edge of the Graphics chip.. this epoxy is used to help secure the chip to the motherboard...
This is a process that is Hand Done at the Factory.. And Some Boards Will Have Only A Little Amount of this, Some Will Have Alot of it...And Some are Only Done On The Corner Edges....
If There Is Alot of This On Your Chip, You Might End Up Needing To Carefully (REAL CAREFULLY) Remove as much of this epoxy as able to....You can use a Razor Blade To Lightly Scrape This Off... DO NOT MISS AND SCRATCH THE MOTHERBOARD!!! Go SLOW...
Now Comes The Heating Of The Chip...
Start With The Heat Gun About 6 Inches Away From The Top Of The Quarter Stack..You want to be holding the gun at a 45% angle.. Aim the heat at the Edge of the chip, You Will Start Rotating Around the Chip- around the outer edge of the chip...then use tighter circles concentrating on the quarter stack, then after about 30-40 seconds, slowly move closer to the chip...
Never Move the Heat Gun Closer than the Top Of Your Coin Stack...Then Pull It Back And Slowly Repeat.. The Chip Needs To Get Hot Enough To Re-Melt The Solder Balls On The Underside Of The Graphics Chip Back Down To The Contact Pads On the Motherboard.. and this takes Quite Alot of heating to Do.... You Must Not OVERHEAT the CHip... It Is Best To Underheat it and have to Redo.. than to overheat.. It will cause the solder to break down and even crack/split.. causing failure forever...
This process will take about 3 minutes total.. Once you shut off the Heat Gun.. Leave The Stack of Coins On The Chip And Let Sit For Another 5 minutes..
Now Remove The Coins(carefull they might still be hot)
Remove All Insulation.. Reinstall RAM, CPU, Heatsink and FAN Assembly (and Of Course Thermal Pads or Paste.. Note:. If Paste Is Used.. It Must Be Silver Paste...
Now You Can Connect The Power Button Strip/ Video Cable And The DC Jack Cable.... And Plug In AC adapter .. You're Now Ready To Test For Solid Power and Video....
Upon Sucessful Chip Reflow/Rebake.... You Need To Go To The HP Website..( www.hp.com )..Click on SUPPORT AND DRIVERS, then select...DOWNLOAD DRIVERS AND SOFTWARE....Then either click the box to Auto-Detect System, Or Enter Your Make/Model Info, Once At The Page With All Of Your Drivers.... Choose The BIOS UPDATE Driver..
Choose The Newest Driver And Download/Install It... It Will Reboot The Laptop And Upon Rebooting, Your Fan Will Spin Faster And More Often Due To A Thermal Controller Update In The BIOS Update...

SOURCE: No display .. getting three short beeps, pause,

It's the sound produced by motherboard stating that motherboard is not able to detect the RAM,open the laptop and remove the RAM and clean with a white paper slowly and insert it properly.check it solve your problem otherwise if you have another RAM slot available then try that too. if none work replace with a NEW RAM this will solve your problem

let me know if it's helpful to you

SOURCE: 4 short beeps when powered on..blank screen

Four beeps is a system board trouble code. Try disconnecting all power sources including the CMOS battery and LiOn battery and let it sit for a few... then power it back up and see what you have.