1) Bad graphics chipset,
2) Bad Video Cable, or loose connections,
3) Bad screen Inverter,
4) Bad LCD screen.
A) Graphics chipset:
(Chip and Chipset are slang terms for I.C.
The chipset, or I.C. used for graphics; is the graphics chipset.
More properly known as the G.P.U.
Graphics Processing Unit,http://en.wikipedia.org/wiki/GPU
Laptop OFF, monitor OFF, connect a VGA monitor; to the VGA connector on the laptop. (Port)
(Left side of laptop, if memory serves)
This is a General example of a VGA connector, (Port), and VGA cable,http://en.wikipedia.org/wiki/VGA_Connector
You can use a CRT type of monitor (Looks like a small TV), or a flat LCD screen monitor if it has a VGA cable.
Turn the monitor on. If a CRT type allow it to warm up.
Turn the laptop on.
By factory default settings, the display should show on the external VGA monitor.
You have at least 3 display options available;
1) Internal monitor of laptop ONLY
2) Internal monitor of laptop AND external VGA monitor
3) External VGA monitor ONLY
Press, and hold the Fn key down, and at the SAME time tap once on the F4 key.
(The F4 key is the Display Toggle-Over key)
Hold the Fn key down again, and tap once more on the F4 key.
Same display on external VGA monitor (Red lines), suggests problem with the graphics chipset.
Good display on external VGA monitor means;
1) Video Cable
2) screen Inverter
3) LCD screenhttp://tim.id.au/laptops/hp/hp%20g60%20compaq%20presario%20cq60.pdf
If you find it is one of the three stated above, post back in a Comment; and I'll guide you step by step, in diagnosing.
Will require partial disassembly of laptop, but not very far.
Will also require an ESD wrist strap.
Average cost is around $3 to $6.
Needed to keep from Static shocking, the delicate hardware components inside the laptop.
[All power removed;
Loosen Keyboard, and roll over out of the way. Do NOT disconnect Keyboard Cable.
Remove Keyboard Cover.
Remove Display Bezel.
Remove screws that hold LCD screen to Display Cover, and check Video Cable connections to back of LCD screen.
The plastic frame in front of the LCD screen, is the Display Bezel.
Laptop closed the top cover is the Display Cover.
Just basic instructions. Like I said, I will step by step you through it, if you wish ]
An LCD screen cannot produce light. It needs an additional light source.
A Backlight is the additional light source.
A Backlight can be a CCFL (or more than one), or a series of LED's.
(Light Emitting Diode)
The Compaq Presario CQ61 series of Notebook PC's, uses a single (1) CCFL.
A CCFL is a Cold Cathode Fluorescent Lamp.
Similar to Fluorescent lighting used in homes, and businesses; but on a MUCH smaller scale.
Average thickness is 2mm. That is a little more than 1/16th of an Inch, or about the width of this capital letter -> O <-
Average length is almost as long, as the LCD screen is in height.
View the last 8 photos,http://www.laptoprepair101.com/laptop/2007/12/09/replace-laptop-backlight-ccfl-lamp/
The screen Inverter converts the power (Electricity), from the laptop; for the LCD screen, and Backlight.
Backlighting that uses CCFL, uses a screen Inverter.
Backlighting that uses a series of LED's, May or May Not use a screen Inverter.
It seems when the LED technology first came out, they did.
Later designs do not seem to.