How can I take control of my computer that hass been hacked and won’t even get to the Start menu?
Hovsep's on the right track, but I don't think you need SARDU for this (SARDU is a multiboot creator, more complex than is required here). You just need a bootable antivirus disc (CD or USB).
Use that to boot up your computer, scan the drive and remove the infection(s). Then remove the drive and reboot as usual. You can read the article on the subject at http://www.howtogeek.com/175234/how-to-use-an-antivirus-boot-disc-or-usb-drive-to-ensure-your-computer-is-clean/ for more details.
Some good bootable recovery discs include:
AVAST (you can only create the boot disc from a working copy of the antivirus)
Kaspersky rescue disk 10 (downlod the "Distributive" from http://support.kaspersky.co.uk/viruses/rescuedisk#downloads)
AVG Rescue CD (download from http://www.avg.com/gb-en/avg-rescue-cd)
AVIRA Rescue CD (detailed instructions at http://forum.avira.com/wbb/index.php?page=Thread&threadID=82163).
prepare livecd with antimalware like SARDU
boot on it and scan
also which Windows OS you have?