Notebook help..Computer tech required!

[Bane]

My missus has a samsung notebook thing and every so often(more than seems necessary) it has a habit of just stopping and doing a Windows update.
There's no warning of this and it seems to do it whenever it wants.For instance,she was online placing an order,just about to checkout and the screen went black and then started to configure an update.It will then shut down and restart by doing another update configuration more or less axactly the same as the one it has just done.
She is unable to do anything with the comptuer until it has done it's full update and configuration thing which seems to take ages.
She then got it restarted and it has no memory of the site she was on and has emptied the shopping cart.Also,it seeems to affect the IE pages,slowing them down and she has to refresh every page befor it will load.
Anyone have any ideas as to what I could try to stop this from happening?
Or does it sound like some sort of virus?
Any help or suggestions are greatly appreciated as it may stop the thing from being thrown in the fire!

[Baz300]

Can you turn automatic updates off?

My laptop gives me a warning that it is away to restart to apply updates but I can postpone it for up to 4 hours

[bacillus]

I set my updates to "check for updates but let me choose whether to  download and install them" to avoid this sort of thing.

[Bane]

I set my updates to "check for updates but let me choose whether to  download and install them" to avoid this sort of thing.

Thanks chaps,I'll have a look for this setting.