Last week I installed Subversion in my systems and found "Mere-Moments Guide to installing a Subversion server on Windows" very helpful indeed and which minimize my time from googling on for more information's about installation. I found another blog entry for subversion installation with screen-shots about each step during installation. I am sharing both the links here for your reference on installing Subversion and I'm sure it will save your time.
Joe White's Blog: Mere Moments Guide To Installing A Subversion Server On Windows:
http://blog.excastle.com/2005/05/31/mere-moments-guide-to-installing-a-subversion
-server-on-windows/
Team Systems : Setting up a Subversion Server under (Installation steps with screen-shots) Windows:
http://blogs.vertigosoftware.com/teamsystem/archive/2006/01/16/Setting_up_a_Subversion_Server_under_
Windows.aspx
Download the SVNService.zip (the link is no longer available in above blogs):
http://www.stanford.edu/~bsuter/subversion-setup-guide/SVNService.zip