The current kernel for Mandriva 2007.0 is "2.6.17-8mdv". You can get the updated kernel and the kernel source packages at the 'updates' or 'main updates' source you have set up for your system.
If you have not set up any update sources for your system, you should. Use of the update functionality of the package manager is the easiest way to manage and install security patches and bug fixes provided by Mandriva.
To configure updates (An Internet connection is required):
Open the Package Manager (System / Configuration / Packaging / Install Remove & Update Software).
Click the 'Options' Menu and select 'Media manager'.
Click the 'Add' button in the menu at the right.
Click 'Official Updates'.
Click 'Yes'.
You will be presented with a list of available ftp mirrors. Select one in your geographical area, then click 'OK'.
Media manager will download the hdlist.cz file for the media source and set up the Update source you have selected.
Click 'OK' to close Media Manager.
Close the package manager.
Open the package manager again.
Click the left button in the tool bar just above the category tree pane (left) and select 'All Updates'. You should now be able to install any available updates for your system.
Best results are obtained with a broadband connection. If you have a dial up connection, you may wish to select a few updates at a time. When I used dial up, I estimated about 5 minutes per Megabyte for download time.
To update your system kernel, read the official directions
here.
HTH,