Try a different browser if you can. I don't have any machines at my disposal that have Win XP (SP2) on them to mess around with.
Clearly - this is a browser/OS compatibility issue... Version 17 is quite new, only released officially on Nov 20. XP SP2 is old, as I'm sure you know, as Windows XP has SP3.
The buttons and formatting options are still there in every browser I've tried on this Win 7 machine (Chrome, IE, Firefox, Opera, Safari). I also tried using FF Ver 17 on the XP SP3 machine, and had no issue with the buttons... so again, first... Try using Chrome, and see if that restores the buttons.
You could also try going here ->
http://www.scubaboard.com/forums/profile.php?do=editoptions and down - second from the bottom is this "
Miscellaneous Options" try changing your setting to "Basic Editor - A simple text box" or Standard Editor - Extra formatting controls
The WYSIWYG editor box does use Java, so also make sure your Java is updated to the latest build.
I have made no changes whatsoever to SB over the past month, so there is absolutely no reason that something would stop working for a single user (or even potentially a small handful of users) without some external cause.