Off Topic Question - Update.inf file

[KENNETH JANUSZ]

Yesterday I got hit with the Blaster Bug.  To make a long story short I cannot apply the MS fix to my XP Prof. since I don't have the Update.inf file.  Would like some feedback on where I can locate it and what directory it belongs in.  I'm on XP Prof. SP1.  I tried apply SP1a and it errored out saying it needed this file also.   TIA,   Ken Janusz, CPIM