suggest me a gud mobo as my old mobo is dead. asus preferred and budget is 100-120$ [5k-6k INR]
Can your Dell case hold a full ATX motherboard?
Also, if your CPU cooler is held in with 4 screws you will find you'll be needing a new cooler to go along with the new motherboard.
You may also find your new motherboard will not fit in the Dell case, so you might also need a new case to go with that.