"DirectShow not installed" error on Win7

[naskoboy]

I have BSPlayer PRO 2.51 (Build 1022) installed on Windows7 Pro.
Every time I try to open any video file I get error "DirectShow not installed".

Then this message pops up "BS.Player cannot play the media file.
You don't have necessary codec installed, file may damaged or not media file.
Click 'Find codec' to try to find codec."
Then when CodecsManager kicks in it throws error "No codec was found. File may be damaged or codec not yet in DB".

BSPlayer FREE works just fine on the same system. Windows Media Player also works. Makes no sense to me. If codec was missing no other player would work, right ?
(I think that 1st FREE version I uninstalled month ago messed up the system somehow and prevents PRO version from properly installing. How can I do clean PRO installation ?)

Your help would be appreciated.