taking owership of file in vista(yes vista)

To take ownership of the file, you'll need to use the takeown command.
Here's an example:

takeown /f C:\Windows\System32\en-US\winload.exe.mui

That will give you ownership of the file, but you still have no rights to delete it.
Now you can run the cacls command to give yourself full control rights to the file:

cacls C:\Windows\System32\en-US\winload.exe.mui /G geek:F

Note that my username is geek, so you will substitute your username there.
At this point, you should be able to delete the file. If you still can't do so, you
may need to reboot into Safe Mode and try it again. For the filename in the
example, I was able to overwrite it without safe mode, but your mileage may vary.