I have simpletech external storage.

You can try going in the add / remove and uninstalling the program, then go into devices and remove from there as well. Also go to the folder it is still listed in and find the uninstall there. Delete all those to your recycle bin. Reboot twice! Then on the 2nd reboot, plug the external in and make sure it has power and is turned on. See if it reappears again.

On another site, this next bit is what someone else tried (the last one), see if that works for you.
Storage forum Simpledrive 1TB External HDD Problem

Go to task Manager > processes tab and find the StorageSync program and end process. Unplug the drive, shut down the PC, replug and start up the Pc and try again.

If you have a SimpleTech SimpleDrive connected to your computer and you're experiencing problems with the external hard drive, there may be several reasons why it's malfunctioning. Troubleshooting your computer can help rule out common problems and the possibility that the hard drive may be defective. If you recently purchased the device and suspect there is something wrong with it, return the defective drive to SimpleTech or the reseller for a replacement.

Incompatible USB Port Problems W 7 First, please disconnect all USB devices and then perform the following steps:


Click "Start" button, type "devmgmt.msc" (without quotation marks) in the "Search" bar and press "Enter". Click "Continue" if necessary.


In Device Manager, double click to expand "Universal Serial Bus controllers", right click on the Host Controller, click "Uninstall" and click "OK".


Repeat the step 2 to uninstall all items under "Universal Serial Bus controllers".



Then, restart your computer and Windows 7 will reinstall all USB controllers automatically. for XP or earlier click start right click on computer select properties device manager scroll down universal serial bus controllers you could see a yellow question / exclamation mark? ! or a red X you will need to update/reinstall drivers right click to reinstall drivers if you can see your usb drive but its not working ports (com&lpt) right click update driver if this fails to fix the problem Check the USB leads that attach to the motherboard usually red white green black make sure they are securely seated and have no dust build up on them dust will cause static and a lot of unforeseen problems to a computer and its parts b> SimpleTech SimpleDrive plug and play options makes it easy for you to connect the device to your computer. But you may encounter problems if your computer's USB (Universal Serial Bus) ports are not compatible with the external hard drive. Make sure your ports are powerful enough to operate the drive. USB 2.0 ports are recommended, but if you're using an older computer with 1.0 ports, the hard drive will function much slower or you may receive an error message that the device is not compatible with your system. b> Missing External Drive Letter b> If you're unable to find the SimpleTech external hard drive's letter on your desktop after you have installed the drivers for the device, it's possible that the external drive may be assigned to another drive. Sometimes, the hard drive is assigned to a network drive and you may need to manually change the drive's letter in Disk Management. Enable Drive Letter View b> Click the "Start" button and choose "Control Panel" from the start menu. Click "Folder Options" and navigate to the "View" tab. Scroll down and place a mark next to "Show drive letters," then click "OK." b> Configuring Drive Manager b> Click the "Start" button to launch the start menu. Right-click "Computer" and choose "Manage" from the menu. Click "Storage" in the menu on the right side to extend the section. Click "Disk Management" under the "Storage" header. This will show you a list of drives and removable storage on your computer. It will also report the status of the drives, such as "Healthy." If the removable storage does not have a drive letter or has a drive letter in conflict with another drive, you can assign it a new letter. Right-click the icon of your removable storage drive and click "Change Drive Letter and Paths." Click the "Change" button, then choose a drive letter from the drop-down menu. Select a letter that is near to the end of the alphabet to prevent drive overlap issues. Click "OK" to allow the changes to take place. You should now see the removable storage listed with your other drives on the "My Computer" screen. SimpleTech SimpleDrive Incorrectly Formatted b> SimpleTech SimpleDrive is normally pre-formatted for Windows NTFS (New Technology File System), but Mac users may need to copy the backup software and reformat the external hard drive for FAT32 or Mac OS to be able to use the external drive. If the external hard drive is not formatted correctly for your system, it may not function or work properly. b> External Hard Drive Inaccessible b> If you receive an error message that says "Drive Inaccessible," the SimpleTech SimpleDrive may not be able to read the service area of the platter. If the external hard drive emits a loud or abnormal sound, this could mean the device is failing. Test the drive on another computer to see if it is working properly. Otherwise, the external hard drive's surface area may be damaged or corrupted. b> Replacing a Defective Hard Drive b> You can return a defective hard drive that is under warranty to SimpleTech. The manufacturer will exchange the device if the seal is not broken. But if you break or tear the seal on the case, any warranty claims will not be accepted and the device will be returned back to you. SimpleTech will only accept the device if you contracted a commercial data recovery company to retrieve critical data from the external hard drive and the seal needed to be broken. Before returning the defective drive, you will need to secure a RMA (Return Merchandise Authorization) approval number from SimpleTech and furnish any invoices or documentation regarding the data recovery company's services.

did you purchase the storage sync program youmight not be able to download that version again unless you pay for it
if you can or want another free backup utility
save this to a document then click on it to open and download second back up free edition

http://dw.com.com/redir?edId=3&siteId=4&oId=3000-2242_4-10405044&ontId=2242_4&lop=linktitle&ltype=dl_elite_gen&pid=10999341&mfgId=6272401&merId=6272401&ttag=lst-4&destUrl=http%3A%2F%2Fdownload.cnet.com%2FSecond-Backup-Free-Edition%2F3000-2242_4-10405044.html

hope this helps

Please check the following link, there you could find the needed drivers:
http://www.hitachigst.com/support/index-files/simpletech-legacy-downloads

The BPA files are the backed up copies of your data. The simpletech utility backs up your files to compresse file ending in BPA. Any computer running the simpletech restore program can extract the data from these files.

You will simply need to install this software on a spare computer in order to test the backups. Frankly though I would just use windows backup to copy the files/folders you want to the drive raw as this can be read anywhere.

Hope this helps FixYa,

Chris

there have been alot of problems in the past with vista not all external components are compatible with this program.i had the same problem with vista so i got rid of vista and started using windows xp home edition since then i have never had a problem with it not recognising any device i have added to my computer.i hope this helps.

try plugging your HD into another desktop/laptop to see if your HD is functioning well on a different computer. Could be the USB cable problem. 

If you go into Computer Management and go to Storage > Disk Management. You'll see the partition there. Right click on it and assign it a drive letter. You will be able to access it from there.

You need to use the Storage Sync program provided with the drive. You can get the latest version at the Simple Tech website