If your Windows computer stopped working in the past week or so then you may have had a type of virus called a Rootkit on your system. Microsoft released a security update this month that unintentionally made a machine stop booting if you were infected. Your best bet if you are not technical is to have someone come copy your data off and setup your machine fresh. There are articles about removing the patch that breaks your machine but if you do that you will simply have a virus infected machine.
One reason to remove the patch would be to then use Microsoft Easy Transfer to move your data to a new machine. If you want to do that then you need to boot from the Windows CD/DVD/USB and start the recovery console. Once the recovery console is launched, type: CHDIR $NtUninstallKB977165 $\spuninst and hit Enter. Then use the following command: BATCH spuninst.txt, hit Enter again, and type: systemroot, and again Enter. At the end customers will need to type: exit. Simply trying to startup Windows without the recovery console will not work, no matter the boot options selected, as the computer will not reboot and Windows will always end up displaying the BSOD.
Once your machine is up and running you can install Windows Easy Transfer;
And that will let you make a good backup of your data so you can wipe your machine out and re-install Windows. Note that any applications like Microsoft Office will need to be re-installed after. Only your files and settings will be backed up.