Maxtor 120 gb harddrive cant read it on older home pc

My maxtor portable 120 gb hard drive running on work pc, with windows xp service pack 2 works fine, when i take it home running on windows xp tried service pack 2, now on 3, working on a 5 year old pc, it knows there is a driver their, though states it''unknown device and error has occured with the device'' once or twice i have recognised it, by luck more than anything, justy unplugging, then plugging in, when it has worked it states it is not working as fast as it could,

my 2gb stick file also does not work, though an older slower smaller stick files works fine, im guessing it something to with the drivers or the hardware of the usb ports, though i really no nothing!

maxtor seem to be a endless loop of no answers and no way to contact their support center.

any ideas

thanks

phil