It's not the screensaver's fault but there seem to be some options enabled in Power Options. To go there, goto Control Panel > Power Options and open it. In the screen before you (tab
Power Schemes) set all 4 options to
never. Those would be:
- Turn off monitor
- Turn off harddisk
- System standby
- System hibernates
They are extremely annoying so disable . So don't forget to check that menu whenever you get to deal with problems like that again

There's also another tab called
Hibernate. If
Enable hibernation is checked, disable it. It will also free up some hdd space.
Jam it back in, in the dark.