Lost HD Space After install/uninstall of updates

Hi I downloaded the updates for Windows XP Pro service pack 1, all updates,
and service pack 2. During the install of SP2 it froze so I decided to do a
system restore to undo the install. Which worked. So I removed all the other
service packs w/ the exception of 1 which cannot be uninstalled. And now I
checked my hard drive space to find that during the install/uninstall of the
service packs it ate up over 4 gigs of hard drive space. Does anyone know
why I lost all that space even after I removed the service packs? How can I
get that space back? It looks like I may have to do a complete reinstall of
windows xp to get my space back. I really dont feel like losing all my
files, music and etc. I would like to get that precious 4 gigs back
considering I only have a 20gig HD anyway, my secondary 40gig HD crapped out,
so this was all I had left. I had half my HD clear w/ over 10 gig free
before the install/uninstall process, now I have little over 6 gigs free.
Someone please, please help me. Thank you.