It's window 7 enterprise. The last time that worked was last month. I don't have any changes made on the computer. Any kind usb device does not worked that's why i having difficulty transferring my files. 

Thank you for your reply.

Hi mitchiboy,

What is the operating system on your computer? Did you make any changes to the computer? When was the last time it was working fine?

Hi mitchiboy,

Do you see any bangs in device manager. please go to this link  http://dell.to/19zbTzI and download the drivers for USB.

Hi Shrikanth,

Thanks for your feedback.I was tried the link you provided many times
but no luck.

Are you saying your USB keyboard and mouse don't work either? Or are you saying it's just the other USB ports that don't work?

USB keyboard and mouse are working better. The problem is when you insert any flash drive the computer can't able to detect. When I looked at the device manager I got exclamation point. I tried all troubleshooting but still no luck. 

Do mouse and/or keyboard work in those ports where the flash drives don't work? And you're sure the flash drives work in another PC?

Version of Windows?

If XP, read this. If Win 7, read this.

Seagate Backup Plus Slim 500GB Portable Hard Drive with Mobile Device Backup USB 3.0 (STCD500102)  It REQUIRES 900MA and the max that ports put out is 500MA.

There is also USB Malware that disables the windows installer.

Flash drives work in other PC. Yes Keyboards and mouse are working in all ports, Except for the usb flash drive. 

This are my troubleshooting.

- Update windows 7. Same Problem

- Update all drives via dell site. Same Problem

- Uninstall the exclamation then scan hardware changes thru Device Manager. Same Problem

- Did System restore. Same Problem

- Updates chipset. Same Problem

- Tried other flash drive even Ipod/Samsung phone did not detected - Same Problem

Did you try the Win 7 fix at the link in my earlier post?

If you reboot in Safe Mode, are those flash drives recognized?

Yes I tried the link you provide however same problem. Even in Safe Mode the flash drive is not detected. 

Have you scanned thoroughly for malware recently?

If you have a Windows Reinstallation optical disk with the exact same version of Windows as is installed, including the same Service Pack, you can try this:

1. Click Start>run
2. Type in: sfc /scannow   (Note: be sure to put 1 space between sfc and /scannow)
3. Click OK

Insert the Windows disk when requested, and reboot when sfc is done. Have patience because it might take ~20-30 min for sfc to run, and the only evidence of what it did will be found in the Windows Event Viewer as "Windows File Protection" entries.

I ran the sfc /scannow but still no luck. In the event viewer the windows file protection does not show.

Device Manager 

The drivers for this device are not installed. (Code 28)

Access is Denied.

To find a driver for this device. Click Update Driver. I

I tried different flash drive and Update Driver but same problem.

Guess the next step would be to run a repair of Windows.

Personal files won't be affected, but it's always wise to back up first.

Thank you for helping me. If I run the windows repair are the licensed applications will deleted?