So I visited Secunia forums and searched for solution. In one of the threads there was a solution mentioned which worked for me.
First rename the present version of PPTVIEW.EXE to PPTVIEW.EXE_OLD in "C:\Program Files\Microsoft Office\Office12\" then download 7-zip from http://www.filehippo.com/download_7-zip and install it. Now download Security Update for PowerPoint Viewer 2007 (KB970059) . Right click on the downloaded file on the desktop -> scroll down to 7Zip and select Extract to as shown in the image

Then find PPTVIEW.EXE_0001in the extracted files and rename it to PPTVIEW.EXE.
Copy and paste it in the following location C:\Program Files\Microsoft Office\Office12\
Now rescan entire system with Secunia PSI it should show powerpoint viewer 2007 in the patched programs list. Visit http://secunia.com/community/forum/thread/show/2624/insecure_but_can_t_get_the_update for more information on this patch.






