Can the usb port provide enough power?

is the usb port power enough to support the board and the new version with fx3?
My laptop's usb port can only provide 500ma current

New version requires 900 mA, which is also standard current for USB 3.0 ports. If your laptop has only USB 2.0 ports, then it probably won't work, becuase USB 2.0 ports are specified only for 500 mA.
PC manufacturers sometimes provide higher currents also for USB 2.0 ports, but this is something that shold be checked in your laptop specifications.

well, i'll prepare a new laptop

Maybe should be better provide some jack for external power (for versions). So we should not be concerned about.
Also, some laptops share the power tracks between the USBs of the internal HUB...

Since I work/research with power electronics, we (my academic group) have to be concerned to isolate the supply of the traditional oscilloscopes. If I could give a option, the new version could be USB isolated and have a jack for external power.