My computer wont recognise my toshiba 320gb portable hard drive.

The format of your drive is probably not correct. If data is not stored on your hard-drive, format it to NTFS if on Windows, or Mac OS Extended (Journaled) if on a Mac. If there is data, back it up to a computer that can read it and then format the drive.

There should be some small screws that hold the case together.

Or, just use a hammer to shatter the case (don't hit too hard) and pry it open, like a ****-shell.

i have toshiba hddr320e04x but my computer cannot detect my device. what should i do?

The drive has failed, Contact the manufacturer for a replacement and if u need the data back, contact a data recovery company :)

Does the drive show in Device Manager? Right click on 'My Computer' and select properties, the open device manager.. Navigate down to Disk Drives or Hard Drives, click on the plus sign and see if your drive is listed. If it is, then right click on the drive name and open properties for the drive. Click on the 'Volumes' tab and hit the 'Populate Button'. It may be the disk just needs initialising, then reformatting before you can use it. If it does need initializing, a wizard should appear to guide you through the process!
If this doesn't solve your problem, try using a different USB cable and/or USB ports on your computer, and ensure to unplug all other USB devices other than keyboard & mouse.

http://www.ehow.com/how_4853479_operating-system-external-hard-drive.html
hope this helps

Sounds like the drive is dead, even though it powers up the disk might not be spinning or the read heads could be stuck. Depending on the data you have on it and if you have it backed up or not, you could send it out for to have the data pulled off it but I warn you it is not cheap.

you need a commercial program like partition magic to do this, there is no sys-built-in way.

use it on a differnet usb port
these portable hard drives have some issues with 1.1 usb ports

how many wattage had your computer? you need to upgrade your power supply.you need also to check your bios setup on usb port