Tab briefly stops working intermittantly

I have 4 PC's (one that has the issue semi-frequently which I've been
using to test the issue on, and the other three that seem to have the
issue occassionally) that intermittantly have problems with the tab
key. All run Windows XP Professional, with Service Pack 2, and all but
one are the same make/model (Dell GX260). The odd one out is a Dell
Lattitude D510. And on the Lattitude it seemed to have occurred thrice
on one day, and after that never again, so I'll pass on that one.

The issue manifests itself by the tabkey just stopping it's functions.
Even weirder, the F5 also seems to have problems at that time. The
Shift-tab key still works tho, so the key itself seems to be fine.
After a period of time and trying, the keys suddenly start working
again normally.

Sofar I've swapped keyboard, to eliminate the hardware error. This
also swapped the PS2 connector over to a USB connector. I also went
ahead and tried installing IntelliType just to make sure the keyboard
driver got refreshed (even if the keyboard used is just the standard
keyboard, with no multimedia or wireless functions whatsoever), aswell
as tried switching on all access settings (like stickykeys and the
like), applying the switching 'm on, then switching 'm all off again,
and re-applying through the access-controlpanel applet.

All to no avail. The issue is known, but only seems limited to
specific software like GroupWise (which we do not use). So while it
doesn't work in one application, it still works in others. Not so in
our case. The key just refuses to work, and all of a sudden it seems
to just pop back into working normally again. To my knowledge no
specific things are tried after which the key doesn't work anymore,
nor are any things specifically tried after which it does work again.

The user is working a lot with the IBM Client Access software (for
AS400 connectivity) and uses the tab frequently and the F5
intermittantly in that program, hence the noticing of the problem.
I've talked to the user however and it doesn't seem limited to doing
something in one program, then switching over to another (for
instance, Outlook 2002) and having the problem. It really seems to be
occurring intermittantly.

I'd expect patches to be the problem, if it weren't for the fact that
I have about 30 of those configurations (all the same PC/model) with
exactly the same patches (WSUS) applied throughout the company, and
only these 4 PC's have reported problems.

I'm at a loss as to what might be going on here, and would like to
submit this to the group to see if anyone can come up with some
suggestion I could try.

Thanks in advance for any and all replies!

Seems this problem was a bit more all-round then first anticipated,
tho I haven't heard from others having the issue then these four.

One of the users found out with some testing that the issue occurred
right after printing. Now we did get some new multifunctionals (Xerox
WorkCenter 7242) here. It turns out it ONLY does this after printing
to that Multifunctional. Printing to a different printer doesn't
affect anything.

Now due to some slow printing issues, we upgraded the PCL driver to
the 5.57.8.0N version (dated March 25th 2008). This also included a
nice (but somewhat annoying) status monitor that would activate upon
printing to the multifunctional. It'd sit in the systemtray for a
fixed amount of time and then close itself down. It shows you running
jobs, completed jobs, aswell as the general info on toners and
papertrays.

Now aslong as the icon for the status monitor sits in the systemtray
(which is for a fixed amount of time after printing), the issue with
the keyboard occurs. If you right click the icon and close it down, it
immidiatly shuts down, and the keyboard immidiatly starts working
again. The Status Monitor wasn't part of the driver we used prior to
this one (which worked slowly over the network), so the problem wasn't
around then.

So... since this is a part of the bidirectional communication with the
printer, we switched it off (properties of the printer, select tab
'Configuration' and then go to the 'Bidirectional Communications'
button. That stopped the Status Monitor from popping up, and thus
prevents the whole tab problem. Users are happy, and I'm happy

Xerox themselves however can't seem to reproduce the issue, so I'm
guessing it's related to some more things then just XP and the
printerdriver, although I have no idea what specifically.

So the problem was more widespread then the 4 machines, but I'm
guessing the rest of the users just doesn't use the tab as much as the
four mentioning the problem.

Just tossing the solution out here so someone else that might run into
this will have some semblance of a solution