Computer is not responding to my external harddrive  

Well there must be something wrong with you usb ports did u try them all i also have this problem my use ports have gone loose so i have to adjust them here. and make sure your computer is up to date that is another issue which might be the problem go to device manager and check for drivers.try exploring the portable hard drive instead of autorun maybe its getting to high for computer to handle 400gb with all the other running programs try closing some unused programs see if that helps.

Hi that must be caused by a virus. before you do anything else try to put your hardrive into someone else computer and if it works fine maybe its you computer that has defect. Try downloading the free usb protector or anti virus protector i forgot. But first i advice you to do step 1. if it doesnt work maybe your hardrive is dead. but it can be fixed, maybe it just the connection cord that is defective, try borrowing also or use another cord if you have extra. Sometime the wiring of the cord split and cannot connect anymore.

the best idea is to restart the computer. if it doesn't work, try external hard drive on different computer if you can. most likely port is not working.

You might want to try to plug it into different system and check if it works or not, if it does, then maybe you need to reinstall some of your computer drivers.

possible if you are using the external 3.5" hard drive ..
1st..your power brick is faulty!
2nd...Your external board is fried

to verify this ..try to plug your hdd directly to a Pc and retry ..

Put your harddisk in fridge for 8-10 hours and then try to attach it with your system. hope it will work..