In my thoughts HP and Dell are very much inferior laptops as compared to Lenovo Thinkpad T series laptops. Don't go for thin laptops, their performance is reduced so that they won't produce heat, as there are no fans installed in those laptops.
I personally don't recommend you to buy a new laptop under this budget. According to my understandings go for branded Lenovo Thinkpad T series laptops with core i7 having atleast 5th or 6th generation. Latest generation will be better. T series laptops are business laptops, they are not cheap laptops, they are the laptops purchased by premium users. One of the most award wining and reliable laptops in the world. Their prices starts from 200k if you purchase a new laptop, but i will recommend you to buy 3-4 years old laptop which will come under 30k with decent amount of RAM.
For better speed buy one with SSD, or pay some additional fee to get with ssd. 16GB Ram is recommended these days.