Desktop hangs on black screen for a while during boot up

[speckytecky]

I have a couple of Windows 7 OS computers that are behaving rather strangely on start up. One is a Lenovo x121e ThinkPad the other a HP 625s laptop. Both boot ok and allow log on but then during the logon process the screen goes black with the active cursor still displayed for about 3 minutes before the desktop finally gets revealed?