i m unable to open ppt files in microsoft office 2007
You can fix it for all files... you need to unblock that file type in the Protected View setting!
Start PowerPoint 2007. On the File tab, click Options, then Trust Center, then the Trust Center Settings button. Next, click Protected View and uncheck "Enable protected view for files originating from the Internet" and click OK.
If you want to disable any of the other blocks, you can do it there too.
You should now be able to open the files. This works in Office 2010 also and will also apply for excel/word
May be your antivirus program is interfering with MS Office interface. Are other MS Office applications working fine? Try disabling the antivirus security and check. If it doesn't work, you can try re installing your MS Office.