S M A was right. I installed the VS2005 run time library and everything was fine.
When I was trying to install the software, the response was that some dlls (those using mfc80 etc) could not be registered.
The simple presance of mfc80 in system32 or/and in installed exe path, did not made any difference.
Regsvr32 was giving a message that could not register the dlls because some information was missing.
Thank you all for the help.