Why it happened:
Check what services are running,
Ctrl alt del
Right click on svchost.exe
If you see that multiple services are running and mostly are from the network group, then most probably this is caused by the automatic windows updates.
You hardly ever updated your windows before and you almost never maintain your system.
The windows automatic updates downloaded too many updates at one time.
When it was trying to download or install the updates there was interruptions e.g your computer was turned off unexpectedly/ the internet connection was unstable.
This may caused corruption in the windows updates files.
The easiest temporary solution is to kill the svchost.exe process that is hogging ur CPU in task manager, but this won't solve the problem in the long term.
Another solution is to install a new clean win7 OS. When you buy a laptop/netbook from certain manufacturers, the OS are cluttered with lots of shitty programs from said manufacturers that will run in the background and hog down your system.
For example, when i bought my vaio netbook there were up to 7 useless vaio default programs that runs during startup.
Such as:"easy networking" which is so stupid because it is just a program that shows u a small window to turn on and off wifi n bluetooth. You don't need it, u can do it in windows and this program is using memory. Especially with a netbook, u have limited CPU n memory, you have not the luxury to waste resources on stupid programs.
Another way to solve this is by downloading iobit uninstaller and uninstall all the default stupid programs. This uninstaller uninstall the programs and ALSO remove the registry and remaining files in your computer to ensure a really clean uninstallation. If you want you can even wipe them permanently from your harddisk so like it has never been installed in your computer.
[You must understand that although u have uninstalled a program, the files can always be retrieved later on from your harddisk and your computer memorizes them in the registry. So a clean uninstallation must be made everytime to avoid conflicts.]
Another solution to solve this problem is by fixing the corruption:
Scroll to windows automatic updates
Go to my computer> windows
Scroll to softwaredistribution folder
Rename it softwaredistributionOLD
Go back to services
Turn the windows automatic updates back on
Reboot your conputer
In this way windows will be forced to recreate a new folder for the window updates and download new files, this solves the corruptions.