[crjdriver]

IMO you are fighting a losing battle. Attempting to upgrade what is now 8yr old hardware is very often an exercise in futility.
Next, nvidia says the minimum pw supply for a standard 1650 is 300W. Here is the nvidia spec sheet for a 1650;
GeForce GTX 1650 Graphics Card | NVIDIA
Going with min spec on anything is not something I would do; up to you. Dell pw supplies are not junk however they are not top of the line either. If someone brought this system to me, I would recommend something around a 400W quality unit.

This is never going to preform like a modern Ryzen or Intel system; just not going to happen.

 

[crjdriver]

So can I go ahead and use a GTX 1650 this Graphic card and Intel core i7 4790k with whatever I have in my computer and just remove the old graphics card and old processor will I be good to go with 300w psu sorry for asking to many questions because I just don't want my computer to be exploded and I recently bought a gaming PC which I never got and it was a scam so I just wanna buy parts for my computer just the GPU and the cpu if I can't use the GTX 1650 can I use the GTX 1050 or 1050 ti with i7 4790k

That really is up to you. I gave you my opinion regarding attempting to upgrade an old dell. If you really have to do this, I always recommend pulling the motherboard out of the case for an intel swap. AMDs can be done it the case without problems. If this is a used cpu you are installing, be sure and clean all parts with 91% or 99% alcohol. When dry, apply new thermal compound IAW [in accordance with] the thermal compound mfg instructions.

 

[crjdriver]

What will be better to use GTX 1650 or GTX 1050/1050ti and I am definitely getting a new CPU so I have to get thermal paste should I be worried using a 300w psu because I don't want to use a different psu I have to remove all the wires and re cable manage them so I don't wanna go through alot of hard work

This has already been explained to you. As for which card, the 1650 is newer; I would go with the newer one.

 

[crjdriver]

Where I used to work, we had at least 3~4000 dell computers. They did a fine job for what we used them for; pilot training, wx forecasts, general office stuff, record keeping, etc however I would NEVER think of attempting to game with one of them. Dells are just not made for gaming [exception being the alienware systems] A well-designed gaming system starts with a performance motherboard, a high-end pw supply, a case with good airflow, etc, etc. Dell [or any big box system] motherboards just do not have the heavy-duty pw regulation, heavy-duty capacitors, extra chipset cooling, reinforced slots for the video card, etc that you find on a high end asus, asrock, or gigabyte motherboard.

While you can install performance parts in a dell, it is analogous to installing a high-performance cam in an econobox car. It will run however it will never run well.

 

[crjdriver]

I really cannot explain it any other way. Any device whether it is a computer, an engine, or anything else is only as strong as the weakest part. In your case, there are a number of weak parts; dell pw supply, motherboard, dell case. Dell stuff is fine for general use; NOT fine for a gaming system.
If you want a system for gaming, either build one OR purchase a gaming system from a reliable mfg.
IMO you are just wasting money attempting to make an old dell into a gaming system.

 

[crjdriver]

I am not going to. I have already explained the problems to you. If you really, really want to put money into an old dell, that is your decision. IMO doing so is a waste of time/money.

 

[crjdriver]

I am going to make one last attempt and it will be the absolutely last time I post in this thread.

at least tell me what to buy like what gpu would be perfect for me

There is no perfect. There is what works for a given task. Can you put that gpu in your system, probably yes as long as you check the length of the slot.

i just want to know in simple words will my computer burn will it blow up

This has already been explained to you numerous times. Going with min spec on a pw supply that is now 8yr old is [IMO] asking for a problem. Does it meet min spec, yes.

If you do not intend on pulling the motherboard to do a cpu swap [which I HIGHLY recommend] be very careful swapping the processor. The pins on that type of processor are in the motherboard socket and not on the processor. The processor has pads which are pretty hard to hurt. The pins in the socket however are very easy to damage.