IIT

Hello Kaptan,
No, you are not eligible to write JEE Mains and Advanced exams. You need to have at least 75% in your board exams. So, even if you clear JEE Mains and advanced, you cannot get any college under JEE counselling.

Yes, if you scored 170 then you get admission in IITs so don't worry just prepare for exam. Check the rank in which you get admission in which college:
http://josaa.nic.in/Result2016/result/OpeningClosingRank.aspx

Check the closing rank of different IITs and NITs and check which college rank is close to your rank:
http://josaa.nic.in/Result2016/result/OpeningClosingRank.aspx
Regards.

It depends upon the branches.

What is your category?

You can try your luck in DTU counselling. IIITs and NITs seem to be tough with this rank but anything is possible. You just need to have patience and wait for all the counselling till spot round. GFTIs are not as much better option as the above two are, so keep that as a back up plan. All the best.

You are eligible for sure but you have to clear JEE Mains and then, you have to clear JEE advanced to get a seat in IIT.

If you are determined to get into CSE in any IIT then you should take a drop.
As your rank is also not good go get admission into any IITs, so you must have to do something either taking a drop or taking admission into some of the private colleges.