RE: Dell Inspiron mini 10 can not connect to internet
You should check your device manager to see what bluetooth you may have installed, and if there are any devices that may need driver updates or are unrecognized by the system.
As for the IP issue. There are many things that can contribute to this. If you have run adware removal recently, some programs can actually remove or reconfigure components essential for network operation. winsockfix is a common tool used to fix this. Ive gone through it myself (while working on a family member's computer who was experiencing similar issues).
You may also try uninstalling and then reinstalling your network card in the device manager. Some people suggest checking your password or removing saved passwords, but seeing as you have already tested multiple networks, the issue is not that.