Sometimes due to certain windows problem, you can't seem to boot up normally in windows. However, it's possible for you to boot up in safe mode.
The problems is when in safe mode, when you plug in the usb drive/ usb external devices, device manager detect the device but the file system doesn't recognize it (possibly is because there's no drive letter assign to the usb)
To enable usb in safe mode, you just need to assign a drive letter in disk management.
1. Go to start --> control panel
2. Switch to classic view (if you haven't switch to classic view - only for windows xp)
3. Select Administrative Tools
4. Select Computer Management
5. Select Disk Management
6. Assign a drive letter by right click on your device
Lastly, backup all your important data to your usb devices and reinstall windows if needed