USB Drive Peculiar Behavior

Running Vista Enterprise RTM - I have two USB 2.0 drives... one 256MB that's
recognized by Vista as simply USBSTOR and a 512 MB Dell that Vista
recognizes as a "M-SysT5 Dell Memory Key USB Device"

Now the 256MB drive behaves normally (at least to me)... it comes up
immediately with "autoplay" prompting my action, e.g. "open folder", etc...
the Dell, on the other hand, either takes up to 3 minutes to be recognized
or doesn't autoplay at all... if I open windows explorer I see the Dell
drive, but if I try to open it, windows explorer crashes (it recovers after
a moment or two)...

There are NO "devices" listed in the control panels "autoplay" screen which
I have set to "Use AutoPlay for all media and devices"... except for audio
and dvd, i have autoplay set to "prompt"...

Vista's using v 6.0.6000.16386 "drivers" for the Dell Drive... WpdFS.dll and
wudfrd.sys are the files... Dell doesn't have drivers for it... I can't
imagine that it would need any...

Anyone got any ideas on why Vista hates this specific USB drive ?? How to
fix it ?

thanks... t