1, if the USB is not recognized by the computer, due to system-driven problems caused by the panic, we can repair by the following methods:
Boot press F8 into safe mode after exiting, select reboot or shutdown in the boot, you can enter the normal mode (repair the registry), if the failure is still, please use the system with the System Restore, restore to you do not appear this time of failure repair (if normal mode recovery failure, Please press F8 to enter into Safe mode using System Restore. Using System disk repair, open a command prompt to enter Sfc/scannow return (there is a space between SFC and//), insert the original system disk repair system, the system will automatically compare the repair. and setting the optical drive in the BIOS to insert the system installation disk into the first boot device press R to select "Repair Installation".
2, if it is a U disk plugged into the computer, the computer prompts "unrecognized equipment" failure caused by the crash, diagnostic methods are as follows:
If the U disk inserted into the computer, the computer prompts "unrecognized equipment", the U disk's power supply circuit is normal. Then check the USB connection circuit failure of u disk. if u disk USB interface circuit is normal, it may be a clock circuit failure (U disk clock frequency and computer can not be synchronized). Then detect the crystal oscillator in the clock circuit and harmonic vibration capacitance. If the clock circuit is normal, the main control chip is not working. Detection of the main control chip power supply, if the power supply is normal, then the main chip damage, replacement can be.
3, sometimes due to insufficient USB power supply caused by computer crashes, the solution is as follows:
Use a live Usbhub or a PS/2 adapter with a USB switch. It is also possible that Windows XP by default to open the power-saving mode, resulting in insufficient USB interface, so that the USB interface intermittent failure. Right-click My Computer/Properties/hardware/Device Manager, double-click the Universal serial Bus controller to several "USB Root Hub" to double-click on any one, open the Properties dialog box, switch to the Power Management tab, remove the "allow the computer to turn off this device to save power" before the check, click OK to return, Restart the computer after you have modified the properties of each USB Roothub in turn. USB device can restore stable operation, the frequency as low as possible.