USB problems

[James Clement]

 I recently had to replace my motherboard and CPU.  Since then I have had trouble getting compatibility between my HP 3970 scanner and my Maxtor External Hard drive.   My OS is Windows XP

When I get one to work, then the other will not.  If I get them both to work at the same time, one of them forfeits at the next boot.  The Ext HD operates at USB 2 hi speed or USB 1.1 slow speed.   I do not know if the scanner will work at Hi speed or not, but my HP Prienter, which is older, seems to work well.   Anybody have any ideas??  Thanks

[merlin_2]

Remove the scanner from the device manager and re-boot..pc......now what happens..irq?/

[James Clement]

The device manager does not show the scanner hooked up.  I think it may have removed itself from the USB hub.  Will get it working again and find out which hub is being used.  Then i can try what You suggest the next time I boot up and it is not working.   (Make sense??)