Problem with Accessing Western Digital WD My Passport Essential SE 1 Tb external driver, please guide to resolve problem with windows XP

Go to Control Panel - Administrative Tools - Computer Management Then go into Disk Management. Hopefully you will see a drive with a capacity of about 480 GB (plus or minus), that's your disk.
Right click on it and select change drive letter and change the drive letter to something that isn't in use.
If that doesn't work or it doesn't show up, go into the Device Manager from the Computer Management screen and see if there is anything under disk drives with a yellow or red symbol next to it. If so, right click it, select uninstall, then unplug the disk drive and plug it back in.