Why does my computer have the wrong time?

Why wont my computer recognize more than 2 external HDDs at a time?

• i have four external HDDs that i have bought over many years. i have a windows 7 computer less than a year old. there are 4 USB ports on the back and 2 in the front. i have a 10 port USB hub with its own external power supply. when i plug in my external HDDs only 2 can be recognized at a time. i have tried plugging them all into the computer and hub in a variety of combinations. i have tried plugging them all in then rebooting the computer What i have learn is: all the USB slots work All of the HDDs work The computer can never recognize more than two of them plugged in at a time. any help would be welcome

• Answer:

  there might be a problem with the drive letter assign to it. to check right-click My Computer or Computer >click Manage >click continue if ask >under Computer Management window select Disk Management >at the right pane if you can see all of your four ext. drive, the problem is that they are using the same drive letter. right-click the one with the same letter with the other and click Change Drive letter and Paths >click "Change" >click the down arrow to display the list of letters >select a letter which is not being used by your computer and click OK. a message will appear just click Yes to finish. you do the same with the other one with the same drive letter as the other.