I have an effect here, that starts driving me nuts:

the startup of certain programs is reproducibly delayed by about 30
seconds during which the system does apparently "nothing" (i.e. it hangs
or waits for something but there is no CPU or disk activity), and only
after that time the program starts up. What's esp. annoying is, that it
is blocking the program that has triggered the firing up of an
application during that period, not the application BEING fired up.

What I want to say with this is:
I e.g. click on a link in some mail in Outlook (or a link in any other
program). Outlook goes non-reactive for about 30 seconds after which IE
is finally started up and opens the referenced webpage. Same if I click
on URLs in other programs.

Or I click on a file in Explorer. Explorer (and with it the entire
system's UI) hangs for said 30 seconds or so and only THEN finally the
application corresponding to the filetype (e.g. a text editor or Adobe
Reader or whatever) starts up and loads the file I clicked on.

Strange enough starting the same programs that show such delays via a
desktop icon or the start menu works "immediately" - no delay. So it is
e.g. faster to copy a URL from a mail, fire up IE using the desktop icon
and pasting it into the address field. If I simply doubleclick the URL,
it will fire up only after half a minute.
Or I can fire up my favorite text editor, it comes up immediately and I
can drag the file icon from explorer into the editor and it immediately
loads the file and opens it. If I doubleclick the file's icon in
Explorer it takes forever until the editor comes up and displays that
file (and Explorer is blocked during that time).

I haven't really figured out the "pattern" behind this effect,
yet.Originally I observed this for URLs only and I thought it was an
Internet Explorer problem, but in the meantime I experienced this with
all kinds of other applications as well. The only common denominator I
see, is that the delays seem to happen always then, when the system has
to determine which application it shold start based on a given filename
or URL (or MIME-type). Could it be that the mechanism that derives the
application responsible for a given file- or MIME-type could be the
problem here?

Does that ring a bell with someone? Any idea, what could cause these
delays? And/or how to fix it?

Michael