I have Sony Vaio pcg 21313m laptop and I've just installed Windows 8 on it.
The problem is I can't find any drivers I need for it. For instance, the wifi doesn't work out of the box. I suppose it's because it doesn't have appropriate drivers, but I might be wrong.
Where coluld I get the drivers?
Since this is not a Windows 8 system, there are no Windows 8 drivers for it. You might be able to force some of the Windows 7 drivers, perhaps by installing them in compatibility mode (right click on installer -> properties -> compatibility -> Run this program in compatibility mode for:...).
Maybe support for it ended? I don't get a lot of relevant searches in Google, even when browsing global results. You may have to go to the component manufacturer sites for the drivers and hope they work (Sony likes to be proprietary, even with drivers).
Realtek's site for realtek audio and LAN drivers, Intel's site for Intel storage and chipset drivers, etc.
Do Windows updates find any drivers? If you have no LAN and no WiFi driver to connect to the internet, you can try using an Ethernet USB adapter to get online with it.
You can also try things like DriverPack Solution and/or 3Dp Chip.