Installation of IE 7.00

My computer is on a network and recently stopped automatic updates. I have
tried all the solutions on this sight in connection with error code
0x8024402c to no avail. However this morning when I booted up the yellow icon
was in the system tray, when I launched it to my surprise it installed a
service pack for office XP but failed to install IE 7 with the following
error message “Set-up could not verify integrity of files needed for
installation make sure cryptographic services are running�. I checked this
via services.msc and it is running? There have been no changes made on the
server, why would these problems suddenly have happened? What do I need to do
for a solution?
Many Thanks
Rob