You can't download 'file extensions'. What your computer needs are the "applications" that allow you to open these files.
Your XP most likely already has most generic or default applications to open most files, eg an image viewer or editor for nearly all image file types, (MSPaint will open most image file types), and a media player for nearly all video file types, (Windows Media Player, or WMP, for most normal video types, or perhaps Quicktime for Apple MOV video files), so I suspect the problem is either how you are trying to open these files, or the problem is with the sender of the emails.
With videos I would never try and open the video direct from the email. Instead I would right click the video attachment and select Save As, and save the file to some convenient location on your hard disk. I use the Desktop for temporary storage. Then I can scan that file for viruses first, before opening the file to watch the video.
If you receive a Powerpoint presentation file, (file extension .pps), then save it the same as videos. If you have Microsoft Office suite installed then you may be able to view the presentation after a virus check by opening the file. If you cannot view it you may need Microsoft's free Powerpoint Viewer from;
Images can be much more of a problem. The difficulty is that the 'senders' can send emails with images in different ways, and they themselves may not know how to send them properly. Here are some of the methods;
1] As an attachment. The sender composes the email then uses the Attachment menu option to attach images stored on their hard drive. If they don't do that right you may not get the images. If the image does not show up in the email, right click the attachment and save it to your hard drive as described above. Then view it from there.
2] Inline: This means as the sender composes the email, he/she 'inserts' an image into the email itself. If they have done that right, then your email software needs to be able to view emails in HTML format.
3] As a link from a web site. The composed email includes a link to an image on a web site, but often they select the wrong web site link, or by the time you get the email the web site itself has changed and moved or deleted that image.
I hope that helps.
I get a lot of emails from friends which include photographs and sometimes video clips. From time to time I am unable to open the pics and videos. Either the pics will appear as a little red x, or the page remains blank, while the message on the video screen tells me there is no file associated with it.
I understand this is all about having the file extension already downloaded onto my computer. I have the jpg's and gif's etc, which enable me to open most attachments OK, but not the occasional unusual ones, while sometimes there is no file extension shown at all (merely the size of the file)and the pics will either appear OK, or will come out in hieroglyphics.
Can anyone tell me where to find the unusual file extensions, how do I download them, and what do I then have to do to enable me to open the attachments whenever I get an email with the same file extension?
XP service pack 3