I lost my simpledrive software

USB - unplug then plug back in. then right click open check properties make sure you set "security" to read & wite & modify or FULL ACCESS.

The power supply for the SimpleTech SimpleDrive Pinafarina is 12V, 2A tip positive.

Check the cable or if possible change the usb cable for another one.

Yes, but there are many recovery software that you can download from the internet.... so don't worry, try 4shared.com by searching Recover My Files which is very effective. Please note to format your HDD using Quick Format rather than Full Format.. Good luck..

From the manufacturer's web-site:

http://www.simpletech.com/commercial/products/simpledriveportablepininfarina.html

follow the link:

http://www.simpletech.com/support/support_downloads_storagesync1.42.php

for the "StorageSync Backup Software Ver. 1.42" software.

I would unplug the external drive then shut down your computer. Plug the drive in(be sure the USB port is in good working order.)Turn the computer on. If it does not recognize the drive search online for tech support for that particular drive. Install any drivers or software. Be sure to find out if the drive is compatible with your operating software. Make sure all connectors are seating firmly and correctly. Make sure that everything is plugged in where it should be plugged in.

have you tried plugging your HD into another computer to see if it has the same problem with another computer? 
if the 2nd computer is able to detect your HD, I suggest a backup of your files and format your HD immediately. Your primary computer should be able to detect it then.
A piece of advice: try removing or unplugging your HD once in awhile. External HD is somewhat different from internal HD. :)

Select your operative system version and dowload drivers and software from this link.
Printer USB must be unplugged when installing drivers. Keep it unplugged for setup procedure, plug it back only when required by software or reinstalling

For which operating system you require if you want for win98 you can download from drivergide.com