如题，无法检测到USB下载器，各位大神帮帮忙，应该怎么办？

我已经重新安装软件了，还是不行

出现的信息如下：

COMMAND: open_cable
INFO: Started ChipScope host (localhost:50001)
INFO: Successfully opened connection to server: localhost:50001 (localhost/127.0.0.1)
INFO: Trying to open Xilinx Platform USB Cable on port USB2
INFO: Trying to open Digilent USB JTAG Cable on port (no port specified)
INFO: Trying to open Xilinx Parallel Cable on port LPT1
INFO: Trying to open Xilinx Parallel Cable on port LPT2
INFO: Trying to open Xilinx Parallel Cable on port LPT3
INFO: Trying to open Xilinx Parallel Cable on port LPT4
ERROR: Failed to detect cable.
Try to open a specific cable from the 'JTAG Chain' menu.