Android tab : skype logged in but status remains invisible and can't chat/voice call through skype

Below option worked:
Cleared the app data (Android settings -> Application Manager - Skype - Clear Data.)
Then able to log in successfully do voice/chat calls. Also able to toggle between Available and Invisible.

Powerpoint file size reduction

1.       Save as PPT 2007 format if its in older format.

2.       Open the file saved in step1.

3.       Scroll and go to a slide where there is a picture.

4.       Click on picture, go to format tab. Select compress pictures.

5.       In Options

6.       Target output : click “e-mail (96 ppi)” & select “automatically perform basic compression on save” & “delete cropped areas of pictures”.

7.       Ok, Ok.

8.       This will reduce file size by almost 50%.

9.       Further can be reduced by publishing it as PDF.

10.   File – Save as : PDF or XPS – Select “Optimize for:” minimum size (publishing online). 

Using above steps a PPT file of size 15 MB got reduced to less than 5 MB.