Windows 7 - usb device not recognized,plz help

well
i have a problem with my usb mass storage.my usb ports read usb mouse,data cables but they do not read pen drives and as i attach a pd,it shows "usb device not recognized" or "device driver not installed". it was working fine in xp but now in win 7 it doesn't. i have installed all drivers and have tried every software but it doesn't work. plz help

motherboard: intel dg31gl essential series

Welcome to the Forums! Couple of things you could try:

1: Make sure you have all required Windows Updates and have run full anti-malware scans.

2: Make sure drivers have been recognized.
a. Type Device Manager in the start orb search field.
b. Click on Device Manager.
c. Check for any warnings (yellow triangle with black exclamation mark or red X.)
d. If any warnings appear, double click and follow prompts to repair.

3: Reinstall USB controller(s).
a. Type Device Manager in the start orb search field.
b. Click on Device Manager.
c. Expand Universal Serial Bus controllers.
d. Right-click every device under the Universal Serial Bus controllers node, and then click Uninstall to remove them one at a time.
e. Restart the computer.Windows will automatically install drivers for the controllers. See if this solves issue.

4: Set USB selective suspend to Disabled.
a. Go to Start, type Power Options in the start field and press Enter.
b. Select Change plan settings next to the power plan you want to edit.
c. Select Change advanced power settings.
d. Select Change settings that are currently unavailable.
e. Set USB selective suspend setting to Disabled under USB settings and then click OK to save the changes.

Please post back if any of these help so we can learn from your experiences.