I need guidance , Which is best for me .. mainframe or .net ?

I am Sreedhar by name and I reside in Trivandrum. I have completed my Bachelors of Engineering in Electrical and Electronics. To be flat open I didnt shine in that course and so i ended up with no job . Now I am nowhere of geting a job except in a call centre. But I know call centre does not promise great future. so I want to do an software course. I dont know the XYZ of any software .... All I heard is that .Net and mainframe courses are the best available options in front of me... I dont know what to select since i dont have any hands on or heads on experience in software field. If there is availability of other courses also please answer me honestly and briefly. Your answer may decide my Future...!!!