Screen Backlight shuts off when fan comes on.

Im sorry about your situation.

Does the computer turn on??
If the computer turns on do you hear or can you see the fan working??

If the computer turns on does it stay on or does it shut down after a few minutes??

This will help us determine what is going on.

hmmm.. seems had a problem directly on the hardware side of your computer. my only and good recommendations to you is, first, check if your packard bell desktop has or still have a Warranty, if its on warranty, you can go to the service center to check the hardware of your PC. Second, if your computer is Out of Warranty you can check it by your self, open your CPU Drive, clean the dust inside the Hardware then check everything if all the wire's are still INTACT to each other.

Fan bearing dry. Lubricate shaft as close to fan body as possible as temporary fix. May need to renew fan soon.

This is due to the inverter for the backlight, or the backlight itself going bad. You are going to be better off replacing the screen unless you are handy with electronics.

Sounds like the backlight may be on its way out.

Put a large font single word onto the screen in a high contrast such as white on black. Get the monitor near a window if possible, and the next time the monitor seems to go off, see if you can still feintly see the image using natural light.

The backlight can be replaced, but it is somtimes so expensive, it's easier to buy a new monitor.

How old is it?

whenever you want to turn it off, put it on hibernate.

Bad power supply or backlight inverter.

If the backlight is not turning on, you should be able to see the lcd image by shining a bright flashlight at the screen.

Backlight inverters are loud, so you can hear them operating (high pitched whine) and if the backlight is coming on, you can see white light leaking around the edge of the screen, and even a little inside the cabinet.

Philips are legendary for having power supplies that fail due to bad capacitors, so that could be the culprit as well.

The backlight is the light bult that illuminates the screen. Before it finally goes out completely it will turn your screen a pink color on startup (and then usually become brighter and the pink fades). It is also possible that the backlight, also called a Cold Cathode Flourescent Light, CCFL, died an immediate death. But usually they take a while and signal with the "PINKNESS" first. If you found that your computer is working just fine connected to an external monitor (and you moved the base of your laptop around while connected to the monitor to be sure and left the computer on for a long time) then you have verified that the screen is the problem. It is usually two things: (1) the inverter, a circuit board that increases the voltage to supply the LCD which eats around 700 volts (yeah baby); or (2) the backlight itself. The first problem is a relatively easy and inexpensive fix. You can find how to replace an inverter by downloading the Hardware Maintenance Manual for the T40, T41, etc., from IBM/Lenovo's site. Replacing the backlight itself, a bulb that is like a strand of speghetti and even more delicate, is a tougher job. I would suggest purchasing a replacement screen in that event rather than replacing the backlight yourself. (The HMM probably does not show you how to replace the backlight/CCFL as it is a potentially dangerous job.) That suggestion assumes you can find a cost-effective replacement screen and do not mind opening the TP and putting the new screen in. At least look at the HMM to see what is involved. Good luck.

Hi...there,
It's turns blue to power safe mode (yellow) it's prevent futher damaged to your monitor. It's seems you got a busted backlight inverter. Need to replaced a new one...Since you only got it for a few months, send it back to Acer for a replacement of a new backlight inverter... Have a nice day!

Hi,
As per your description, I find that the issue is with the LCD Backlight which is also called as LCD Inverter which lights up the LCD to show us the Display on the LCD Display.
If this Backlight is gone bad, you will be barely able to see the Display on the LCD.
Coming to the Noise you had mentioned above can be from the Cooling fans of the Notebook which will be spinning at high speed when the Notebook starts and will reduce gradually after few minutes.
I recommend you to try cleaning the Cooling fan vents using any Vacuum Cleaner or Air Blower.
I recommend you to contact any nearest HP Authorized Service Center and get the LCD Backlight replaced.
Hope this helps....