This could be for a variety of reasons depending on the order on blinks (like 2 blinks, then pause, then 3 blinks, etc).
The most common issues can be connected to:
RAM, in which case you just have to reseat them like this
Faulty Power Supply, in which case you have to replace it.
Motherboard, one possible solution could be to do a jumper reset: If your motherboard looks like This, there's a little blue thingy on the top right of the picture that can be removed. That's the jumper. Remove it, turn on your pc, then turn it off, replug the jumper, and turn on your pc again. (Obviously unplug every cable before doing anything inside your PC)
If it still doesn't work, even after googling your issue, contact dell support or take your PC to a repair shop.
The most common issues can be connected to:
RAM, in which case you just have to reseat them like this
Faulty Power Supply, in which case you have to replace it.
Motherboard, one possible solution could be to do a jumper reset: If your motherboard looks like This, there's a little blue thingy on the top right of the picture that can be removed. That's the jumper. Remove it, turn on your pc, then turn it off, replug the jumper, and turn on your pc again. (Obviously unplug every cable before doing anything inside your PC)
If it still doesn't work, even after googling your issue, contact dell support or take your PC to a repair shop.
