Here are some brief instructions on how to change the default keyboard in XP (Windows 7 and Vista procedures are very similar)

1. Click Start
2. Choose "Control Panel"
3. Double Click "Regional and Language Options" (Change keyboards and other input methods in W7/Vista)
4. Click the 'Languages' tab
5. Click 'Details"
6. In the drop-down list at the top choose the language you want to use.
7. Click OK
8. Click OK again

This will change the keyboard layout to the language chosen. 

If you need to add a keyboard (so that you can swap between them) then:

1. Follow steps 1 to 5
2. Click 'Add'
3. Choose the language you want
4. Click OK
5. Continue from step 6 above to choose your default

For an easy way to change from one layout to another you should enable the 'Language Bar':

1. Follow steps 1 to 5 above
2. Click "Language Bar..."
3. Tick the "Show the Language bar on the desktop" option
4. Click OK
5. Continue from step 6 above

You will now have something like 'EN' or 'ES' on your taskbar at the bottom of your screen. Click this to change layout as needed.

I have personally received a number of warnings about a "Invitation FACEBOOK" message that will delete my hard drive. It is, of course, a hoax.

This is what Hoaxslayer has to say about it:

According to yet another "virus" warning that is rapidly making its way around social network Facebook, users should watch out for messages with an attachment named "Invitation Fb". The warning claims that the attachment contains an Olympic torch virus that "will take the whole hard disk C" on the infected computer. The message further claims that this virus has been classified by Microsoft as the worst ever.

However the claims in the message are total nonsense. There is no virus like the one described in the warning. In fact, the message is nothing more than a Facebook flavoured variant of a tired old virus hoax that has circulated via email since 2006. As the following example of the 2006 email version reveals, the two are clearly woven from the very same cloth:

You should be alert during the next days: Do not open any message with an attached filed called "Invitation" regardless of who sent it. It is a virus that opens an Olympic Torch which "burns" the whole hard disc C of your computer. This is the worst virus announced by CNN, it has been classified by Microsoft as the most destructive virus ever.
And the original Olympic Torch hoax was itself derived from an even earlier hoax email that began circulating more than a decade ago. Several other hoax messages based on the same "Olympic Torch" theme have circulated since 2006. None have contained even a shred of truth.

Spreading false virus warnings will help nobody. If this hoax message appears on your Facebook page, please do not repost it. And please help to stop its spread by informing the poster and other users that the message is a hoax.