When i plug anything into the usb on the...

hi there
i have a nec versa e 2000 and yesterday i plugged in a external dvd driver and the lappy shutdown on me, when i tried to boot bac up it went to windows logo and restarted again after several times of it happening i left it off for a few then booted the lappy bac up , when i got it going again i want able to get anyhting i plugged in to the usb to work i tried all the usb points and nothing happened. i have checked bios and it says it is enabled, i uninstalled files and tried to get them installed but nothing , desperate help needed
ty in advance