[CentOS] USB Drive is detected and but the device "/dev/sda1" is not initialized

Dear All,

    I have using CentOS 4.4 and My PC USB Drive is detected and
    but the device "/dev/sda1" is not initialized and i have executed the
    dmesg command and I am getting the following messages
   
    usb 1-6: new high speed USB device using address 2
    SCSI subsystem initialized
    Initializing USB Mass Storage driver...
    scsi0 : SCSI emulation for USB Mass Storage devices
      Vendor: JetFlash  Model: TS1GJFV30         Rev: 8.07
      Type:   Direct-Access                      ANSI SCSI revision: 02
    USB Mass Storage device found at 2
    usbcore: registered new driver usb-storage
    USB Mass Storage support registered.
    SCSI device sda: 1986558 512-byte hdwr sectors (1017 MB)
    sda: Write Protect is off
    sda: Mode Sense: 03 00 00 00
    sda: assuming drive cache: write through
    SCSI device sda: 1986558 512-byte hdwr sectors (1017 MB)
    sda: Write Protect is off
    sda: Mode Sense: 03 00 00 00
    sda: assuming drive cache: write through
    sda:
    Attached scsi removable disk sda at scsi0, channel 0, id 0, lun 0

    and i have tried in windows xp service pack 2 system USB Drive is 
detected
    but can not opened and i am getting the following message please 
insert disk in drive

    I am not sure why this is happening. Can some one throw light on this.


Regards
-S.Balaji