Hi, guys! I saw a really wonderful post by MrTasselhof for rooting your tablet easily. You may see it from here
Or I repeat the post here:

I used Moborobo and superoneclick to root my n90, , give a go.

I can confirm that this method works for rooting the device.
The instructions are VERY simple.
1) Link:
2) Download this modified SuperOneClick - Short Fuse
3) Install Moborobo and open it
4) Make sure USB Debugging is enabled on your tablet (Settings --> Developer Options)
5) Connect your Window N90 Dual Core tablet to your PC
6) Wait for Moborobo to see the device
7) Extract the contents of
8) Run SuperOneClick.exe
9) Click on Root
10) Click on Yes (it says device is already rooted do you wish to continue)

That's it... you are all done and ROOTED!