USB devices not present after suspend mode (!?)

Hi, since the SP1 are installed i have this behaviour that if the PC was in
the suspend (standby) mode and wakes up all usb devices are out off function
(!?)

this hapens not every time, only (i asume) around 5% from the wakup!

> the pc its a mediacenter and if no usb devices are available like the
> remote control, keyboard or mouse... its not funny

is there a way that vista can reinitialize the usb drivers/hub/devices like
a cold start?

thank you for any help
Volkan