Thank you both for your answers.
Based on the age of your system you may have an aged related hardware fault -hard drive or motherboard.
My computer is 4 years old now, but I had the same problem 2 years ago, when it was 2 years old, only.
That is why I decided 7-8 months ago to clean re-install Windows 7, but this didn't help.
Have you run the western digital drive diagnostics for example to see if you have a possible problem with it?
Yes, I have a month ago - the HD passed.
I have 3 volumes: system reserved (100 MB), volume C: (60 MB with the OS) and volume D: 693 MB.
Lately I checked again the file systems on C: and D:. They look OK, but I get event viewer messages,
that something is wrong with the system reserved partition.
For the moment I am not sure how to check it, or if it could be repaired somehow.
If it was me I would update the bios to the latest and then make sure all your drivers are up to date.
I want to try to update the BIOS using @BIOS from Windows. I read the instruction in the motherboard's manual,
but it is not very detailed.
The instruction starts with : In Windows, close all applications and TSR (Terminate and Stay Resident) programs.
This helps prevent unexpected failures when performing a BIOS update.
How to close all TSR programs in Windows 7?
I already downloaded the last update file for my BIOS, extracted it and saved it to the desktop.
According to the instruction for using @BIOS I can choose the option "Update BIOS from file".
I am not sure which of the 3 extracted files to use. Maybe the last one? The 3 files are:
autoexec
FLASHSPI
G31MES2L.FI
The instruction says, that after I click Update BIOS from file, I have to select the
location, where I saved
the BIOS update file. What does that mean? Do I have just to select the folder on the desktop, containing the 3 extracted
files, or open the folder and select one of these 3 files?
Once this is done, I have to follow the on-screen instructions to complete. Do I have to know anything in advance, so I won't
make a mistake?
The next step for me is to click "Save the Current BIOS File". What does that mean? Is it saving the new BIOS file?
Or is it saving the old BIOS somewhere, just in case?
Then I have to select "Load BIOS Defaults after BIOS update" check box and re-start the computer.
There was a warning as well not to try to overclock the system at this moment. What does that mean?
And as far as I understand my motherboard supports DualBIOS. Does that mean, that when I update the BIOS I will
automatically update both the main BIOS and the backup BIOS?
I checked through the Device Manager one by one if my drivers were up to date. It found only 1 driver, that needed updating
and this was ATI Radeon HD 4670. I updated it. Is Windows Device Manager information correct? Can I rely on it?
Can you, please help with some details about the whole procedure? Thank you.
As far as dmdilks suggestion, I might try it if BIOS updating fails, but I have never ever opened my(any) computer.
Maybe I have to do it anyway, at least to clean the dust....