Computer not showing USB Drives

I have a new Poweredge SC420 running Windows XP (service pack 2).  Otherwise it is running fine.  The problem is that when I try to use a USB port, it does not display the "drive" that should be created.  For example, when I insert a jumpdrive, it correctly scans it, installs it and says the drive is available for use.  However, when I look in Windows Explorer or My Computer, it does not show the jumpdrive as a "drive".  It only shows my hard drives and CD drives (2 of each).  On other computers, the jumpdrive will show up as a new "drive" and is accessible just as any other harddrive.  The same is true when I try connecting a digital camera.  Normally it would show as a new drive but with this machine, it does not show up at all although it is saying it has installed everything.  I have gone into Control Panel-System-Device Manager and verified that it is present and working properly as a USB device but still it is not listed.  There must be somewhere I have to switch something or whatever to make it display new drives (I tried using refresh on the explorer and my computer screens).  I know the devices work because they worked properly on other machines and I tried different USB ports on this machine.

 

Please help.