I bought my laptop with Vista OS installed, after a few months i downgraded to XP (a lot of problems to install SATA drive) then the keyboard went crazy: F10 and F11 keys are always on.
I can type correctly only when i hold the Fn (function) key.
I also have problems with the mouse pad: can't configure it correctly.

Where can I find the correct XP drivers set?

a lot of new laptops only have vista drivers written for the things you mention you are having problems with ,no xp drivers .i assume you already tried toshiba for xp drivers

yea and the only way to beat it is to join it.... back to vista.
unless you have an XP recovery image from Toshiba. that will work better than the downgrade because all the drivers are preloaded.