XP-Pro Desktop boot up delay

My second Dell Pc running Win XPpro was working just fine until yesterday.

I entered my system's Bios to check the type of hard drive, just viewed
category, changed nothing, then exited.

Ever since that when Windows boots, I get the Welcome screen and the startup
music. But when I click on my account it takes approx 60 secs to open to the
desktop where upon the desktop background picture is presented but absolutely
no icons, no task bars, no start menu, nothing. If I wait approx another 120
secs, all appear and everything functions as normal. While there is nothing
on the desktop, I can ctl-alt-delete and access the Task Manager which shows
no applications are running and the user tab shows me correctly, processes
appear loaded.
Shutdown is normal, switching users is normal, just the boot up issue.

Any ideas what is wrong or how to troubleshoot this?