(1) You don't "paste" fonts into the Fonts folder; you "install" them;
the easiest way to do it is to right-click on the name, in whichever
folder it happens to be stored in, and choose Install. In Vista and
2007, you don't even have to close and reopen Word for the font to
become available for use.
(2) You did indeed have Hebrew fonts in your system already -- as I
said, both Times New Roman and Arial Unicode include Hebrew (and much
else).
(3) However, you've just revealed that this document started out in
WordPerfect, which means all bets are off. It's well known here that
some WP fonts do not conform to Unicode, so it's very likely that WP
Hebrew also doesn't; which means that even if you've gotten the
letters to appear correctly, Word doesn't know that they're supposed
to be Hebrew, so it doesn't display them right-to-left. If you don't
simply retype your Hebrew text using a standard font, no one else who
doesn't happen to have this legacy WP font will be able to read it,
either.
(4) Now that you've installed Hebrew in your Windows system, you'll
see that a new icon now appears near the right end of the Windows (not
Word) status bar (very bottom of your screen), a square with EN. Click
on that, and choose Hebrew instead. (Or, toggle between them with Alt
+Shift.) In order to see the keyboard you're using, go to Start > All
Programs > Accessories > Accessibility > On-screen Keyboard. Now, when
your cursor is in a document where Hebrew is selected, move your
cursor over the on-screen keyboard and it will show you the Hebrew
letters. (If you need vowels, IIRC you get them with a combination of
CapsLock and Shift and they're way too small to see on the On-screen
Keyboard.) You then type either by typing on your keyboard, or by
clicking on the on-screen key images.