You mean you can't boot into Linux because setup was damaged, and Windows won't boot at all? Or do you mean Windows does boot, but Linux does not?
Anycase, I'd do this: since your Linux setup should not have done anything with your Windows partitions, just insert the Linux setup disc in and restart the installation; if you created partitions before the power failure, and are asked, just overwrite Linux partitions
(not all, i.e. Windows ones) and go ahead as you would normally do. In the end a bootloader is installed anyway, so unless you removed or touched your Windows partitions during the setup, you should be fine. Or if you did, you should know what you did and how it's undone if possible
To just "recover Windows" and not install Linux at all,
WinXP) boot from the install disc, select Recovery Console from boot menu and run fixmbr
Older Windows versions) from a command prompt, run fdisk \mbr
...after which just remove the Linux partitions (if any) with any partitioning software capable of that (Windows' system tools can do that) and format the free space with fdisk
or any partition manager. Or resize your Windows partition to fill the disk.