Help mobile keeps plugging/unplugging itself

[connecting device problem]

I want to install a custom rom so I removed the battery and connected my phone (zopo zp 999) to th pc but it keeps plugging and unplugging.When I tried with my laptop,the same thing happend.I flashed a rom on this one before 2 months and also on other mobiles with no problems.I also tried a different usb but had no luck...so,where is the problem?

 

[funkylogik]

are you supposed to remove the battery?

 

[thgeorge]

yes I am...I even tried keepind the battery on...