Hi Atul
MCA is a postgraduate course and in order to apply for this course you must have an under graduate degree of either BCA or B.Sc. B.Com students cannot apply for MCA. However, if you want to study computers or subjects related to that then it will be better if you apply for certificate courses or else you will have to apply for undergraduate computer course like BCA and start from scratch.
if u r doing bcom nd want to go for MCA y did u choose bcom.....1st nd foremost just think 4 sumtime wat u want to do in life.....nd dat will give u ur answer.....ur heart will give da answer