how many marks get in English, computer in board exam to admission in nits, iits?

To get admission in Engineering colleges, PCM subjects are compulsory. And you need to consider below points as well -

75% percentage should be in 12th class (including all subjects).
The five subjects will be taken into account for calculation of percentile of qualifying examination marksfor paper 1(B.E./B. Tech.)of JEE (Main) which are:

1-Language
2-Physics
3-Mathematics
4-Any one of (Chemistry, Biology, Biotechnology, Technical Vocational Subject)
5-Any other subject

Note: If a candidate has appeared in six subjects in the qualifying examination, the subject (fifth or sixth) with better marks will be considered.

Hope this helps!!!

Good Luck!!!