Software Testing

You can go for various online courses, then you will have to appear for a test to get a certificate.

Visit Websites for this. Look CCNA syllabus. if you can afford prefer a training

Without knowing what did you do in graduation, I would recommend you to undertake a long-term (12-18 months) course from a reputed institute.

obviously evry cmpny needs software testers so they are as important to organization as the developers. but still developers are more preferred than testers as developers for first have high salary than testers and also in almost everythng dev comes first. bt its not like that u cant go in testing. so if u had to choose b/w dev & testing then I suggest u to go for dev bt if u r getting testing then take it and start working.

for s/w testing there is ISTQB. it has levels. u can get detailed data here
http://www.guru99.com/istqb.html