How to access other applications through vb program?

Hi all,
I am a stranger to VB. So please forgive me for silly questions.

How to access other programs from vb program?
(I want to run excel from a vb exe file?)
How to run a macro which is in excel through a vb program ?
("access" is macro written in excel, I want to execute it from a vb exe file)

Thankyou
Regards
Rajamano

have a search through the forums for excel there will be lots of infomation on how to work with excel, the same applies to access :)