I would start with using the Restoration Disk, and when asked do a Non-Destructive restoration.
[Don't have one? Go to HP Support on the internet, then to Contact HP. In the US the disks are free. The shipping and handling is not. $17 for a 5 to 7 day ship, $24 for a 2 to 3 day ship. The designation Presario v6000 just means your computer is one of the Presario v6000 series. The EXACT product number is on the bottom of your laptop. It's in the white Service Tag, and to the left of P/N. Write it down, have it ready to tell the nice people at HP Support. PS. Calling in the US is free. It's a toll-free number ]
Past this I would look into seeing if the Display Cable has become slightly disconnected, or is damaged.
The top cover of your laptop, the LCD screen, the metal frame around the LCD screen, and the frame around the LCD screen in front that you see, (Bezel), is the Display Assembly.
Coming out of the body of the laptop that you do not see, is a Display cable. (And the Wireless Antenna Cable)
Opening and closing the laptop can cause this cable to become disconnected, (Usually slightly), and/or damaged.
(Yes, I know. Who designed this?)
To lead you into reconnecting the Display cable, is going to be lengthy. I don't know your skill prowess, but repairing the cable may be more than you wish to take on.
First you will need to download the Service Manual. It's free from HP Support.
I chose the Compaq Presario V6000AU for an example. All of the v6000 series should fall within this service manual.http://h10025.www1.hp.com/ewfrf/wc/manualCategory?lc=en&dlc=en&cc=us&lang=en&product=3200953&
On this page scroll down to the listing -
Compaq Presario V6000 Notebook PC - Maintenance and Service Guide, and left-click on it.
This is a PDF file. The computer you are on now has Adobe Reader on it, which uses PDF files.
I would suggest upgrading, (Free), to the newest version of Adobe Reader, if your computer does not have it on it.
Adobe Reader 9.3.4
After you click on the above file name, it will take time for the file to download.
You may just see a blank page until the file fully downloads.
Advise be patient.
Page 146 deals with the Display Assembly.
Before working on a laptop, ensure all electrical sources to the laptop are disconnected.
Remove the AC adapter (Charger), and the Battery.
Also follow Anti-Static Precautions.
If you do not know what Anti-Static Precautions are, please post in a Comment ]
Page 147 shows the Display Cable. Enlarge the page for clarity.
(Use the Zoom In tool. The + sign at the top )
The above are the easy repairs. Past this point it gets pretty intricate.
[May be a problem with the graphics chip. The GPU. http://en.wikipedia.org/wiki/GPU
The bottom of the GPU used, (Nvidia GeForce G0 6150. Integrated graphics. GPU is soldered to the motherboard), has pins on the bottom. Contact pins.
The socket these pins insert into is a BGA socket.http://en.wikipedia.org/wiki/Ball_grid_array
Over time, and with the heat involved inside a laptop, the pins become slightly un-soldered from the BGA socket.
This allows a bad connection.
If this is the problem the GPU chip needs to be reworked with a Reflow machine. Not a common piece of equipment in a 'Geeks are us' type of computer repair shop, if you catch my drift.
Repair will be stated as replace the motherboard.
There are other problems that can be afoot, with no easy DIY solution.