Ubuntu DNS error on Virtualbox

Quite often on my Guest Ubuntu system on virtual box, I face this problem, where network is accessible via IP but not my domain name. I am able to ping any IP but DNS resolution fails. In those scenarios I have found the following command quite useful:

sudo dpkg-reconfigure resolvconf

This resets/regenrates the resolv.conf and everything is back to normal :)

How to free up space on Windows?

I have been facing this problem where entire of my drive C had always been full, though it was having almost 50 GB, and no content apart from windows and program files.

I have tried disk clean up and  disk clean up with system files with no effect.

Finally to solve it, I went to I changed the attributed of the files on my drive C:

• Write click on Drive C and click properties.
• In properties, select "Compress drive to save disk space" and unselect "Allow files on the drive to have contents indexed in addition to file properties".
• Press Apply. The process with take a couple of hours on my SSD drive.

and Hola, I had ann extra 7GB of space.

Other Techniques:

1. Reduce the amount of space system restore takes. To do so go to system restore settings in control panel.
2. Reduce the amount of space hibernate files take. Run command prompt as administrator and execute Powercfg.exe /hibernate /size 50 .  Additionally, switch off fast boot up /start up in control panel. This would give you a good amount of space. Stop using hibernate also.
3. Or, Switch off hibernation and fast boot up all together. Run powercfg /h off  from administrator privilege command prompt.

Other important links:
http://windows.microsoft.com/en-in/windows-8/free-up-disk-space