Service Pack slowed system

I dutifully installed SP 1. I opted for "Archive
existing files (This may use significant resources)"
because the Install Wizard said that was necessary if I
ever wanted to remove SP 1.

I didn't realize the "resources" consumed would be on the
hard drive. I'm guessing that's what makes my 2003 Dell
Dimension 8200 so slow since installing SP 1.

Can I partition the hard drive or SOMEHOW reduce the disk
space SP 1 consumes?