Cq40-620la monitor blinks at start up

Without knowing what kind of parts you have, it is quite difficult to make a reasonable diagnosis; however, I would start with checking the following parts:

1. RAM - make sure they're seated properly, and try them in one by one, and in different slots
2. GPU/VGA - If you've got an on-board Video Graphics Accelerator (sometimes called Integrated Video), see what happens when you connect the monitor to this display device, as opposed to an add-on (discrete) Graphics Processing Unit (GPU). Similarly, if you're using on-board VGA, try using a discrete GPU.
3. PSU - Try reducing the load on your Power Supply Unit (PSU). Disconnect unnecessary boot devices (HDD, ODD, case fans, etc.)

I apologize, I should have at least looked up the model number you posted in the title, then I would have known it was a notebook. In regards to the temp issue, unless I read documentation from the manufacturer, I would regard this as a fluke.

There are possibilities that you have intermittent hardware failure. Download and install the following software; they're free:

1. CPU-Z
2. GPU-Z
3. HW Monitor

CPU-Z is a very handy software that will show you what is connected to the motherboard. CPU-Z, like the motherboard, detects RAM via the Serial Presence Detect (SPD) chip embedded in the RAM stick. The SPD chip stores all of the information of your RAM (make, model, channel configuration, etc). Another great feature is that CPU-Z will show you the info on your Central Processing Unit (CPU), hence its name. When you run this program, click on the "Memory" tab to find out what CPU-Z detects. If what you see on this tab doesn't match what should be in there (1 GB installed from factory - upgradable to 3 GB), then this could be your problem.

GPU-Z does something similar to CPU-Z, but the bread and butter of this software is that it monitors your display adapter's temperature. Ideally, the integrated VGA shouldn't exceed ~60 C.

HW Monitor will display the temperatures of the CPU. If your CPU is getting too hot, it is likely that there is a cooling problem inside the notebook. You don't want the CPU temp to get higher than ~50 C, or you run the risk of permanently damaging the CPU.

Considering the age of this notebook, though, it wouldn't be surprising to learn that there is a lot of dust built up inside the notebook. Perhaps the thermal paste that is between the CPU and the heatsink is dried up.

If you continue to experience problems, I recommend that you back up your hard drive and reinstall Windows. If you want to create a disk image (a clone) of your hard drive, I recommend using Acronis True Image. Backing up the hard drive via the disk image method is basically a complex copy and paste routine.

Acronis True Image is a software that uses a Graphical User Interface (GUI) that guides the user in creating a disk image. Once the image is created, save the image to an external hard drive, or if small enough, on a DVD.