Ms NET Frameworks 1.1 Sp1

windows xp 2002 sp2- auto updates on.my last update (ms .NET frameworks 1.1 sp1) came up for an update- i believe my computer rebooted itself before the update/install completed & now the update icon keeps showing up in systray..but it will not install. if i click it to install..it will run (green lines moving) but in end will not install. if i click "custom" & choose not to install..the update icon will always re-appear in systray.how do i fix this- either make it complete the install or permanently skip this install (is it important) but keep autoupdates on??