|"as I remember seller said it's 1GB sized"|
So you bought it used.
In that case you have no way of knowing whether it's been abused.
Apparently the DELL Alienware M15x series is still being sold, but it first came out in October 2009, so your laptop could be as old as that.
"The Most Powerful 15-Inch Gaming Laptop in the Universe"
Released on 10/15/2009
Apparently this series seems to have an actual video CARD that can be installed and removed, rather than a video adapter built into the mboard like most laptops have that cannot be installed or removed.
There are three choices of video CARD it can have - two are ATI, the other is NVidia GTX 260.
* 1024 (MB) ATI HD5730 Mobility RadeonTM
* 1024 (MB) ATI HD5850 Mobility RadeonTM
* 1024 (MB) NVIDIA® GTX260M GeForce
All have 1,024mb (1gb) of video ram. That ram is NOT shared with the ram installed in the mboard, which in your case is 4gb (4,096mb).
"when I go to dxdiag and go to display it says approx total memory is about 494MB..."
If you mean when you click on the Display tab, when you run dxdiag, it says Approximate total memory: 494mb........
I'm not sure what that figure is for or what it should be. On a laptop that may vary, depending on what you're doing at the time. E.g when you don't need as much, the video chipset uses less memory.
That figure may vary depending on which video chipset you're using, on any computer, depending on what you're doing at the time.
To give you an example, I have a Radeon 3650 video chipset on a PCI-E X16 video card on my desktop computer.
Going to the same place - run dxdiag, click on the Display tab - in Vista, which has many things that are identical to the same thing in Windows 7
Approximate total memory: 1784mb
The Radeon 3650 card has 512mb of video ram on it
There is 3gb of ram in the mboard.
The place where you can see how much physical video ram a video card has on it in Windows is System Information.
One way to get there is....
Click on the Windows 7 icon lower left bottom of your main desktop screen.
type: msinfo32 in the Start Search box, press Enter.
On the left side open up Components - click on Display
beside the Adapter Ram line is the physical ram on the video card.
In your case it's 1gb = 1,024mb (1,073,741,824 bytes)
""Has there been a power failure event while the computer was plugged into the AC adapter ?""
"failure event ? I don't understand that,"
As in, the power went off, or a circuit breaker on the circuit the AC adapter was plugged into was tripped off, or there was a power surge or spike - you may have noticed lights briefly being brighter.
"no for the last 1 about lighning, we don't have lighting strikes in my region, at least never heard of it happens here,"
Lightning strikes happen everywhere in the world when the temperature gets warm enough and there is enough moisture in the air for that to happen, whether you were aware of that or not. Unless you live in a desert where it never rains or in the Arctic or Antarctic, lighting does happen in your area.
What I mean is were you aware of there being an event where lightning struck the ground or a building or whatever in your area. Even lightning striking the electrical power grid a long way away can damage your computer when the AC adapter is plugged in.
If you haven't already done so, try cleaning the contacts on the ram and re-seating it.
If you are using any settings in the bios to overclock the cpu or anything else, that COULD cause your problem. In that case if you load bios defaults in the bios the problem should go away.
"it's not overheating,"
How do you know that ?
How hot does it get ?
The current CPU temp is show in the bios Setup.
You may or may not also have a program in Windows that shows you the same things the bios does - the current CPU temp, other temps, fan speeds, voltages.
"and all "where it is" is sitting on the Desk, I don't carry my laptops I just put my laptops in my room on the desk,"
Then why did you buy a laptop ?
You buy a laptop if you need a portable computer and intend to use it in more than one location.
If you don't need a portable computer, then don't buy a laptop.
You always get a better bang for the same money if you buy a desktop computer.