PC turns on with graphics card, but mostly doesn't display anything. How can I fix it?

Hi all, I have a Gaming PC with a Nvidia GeoForce GTX 750 Ti (2048mb) that will boot sometimes but most of the time, no. Even if I try to play a game such as Fortnite the PC freezes and then turns off. I was wondering if there was anyone out there that could help me. I looked all over the internet but found no solutions.

My PC Specifications :


Operating System
Windows 10 Pro 64-bit
CPU
Intel Core i5 2500 @ 3.30GHz 34 °C
Sandy Bridge 32nm Technology
RAM
8.00GB Dual-Channel DDR3 @ 665MHz (9-9-9-25)
Motherboard
MSI H67MA-E45 (MS-7678) (SOCKET 0) 35 °C
Graphics
G276HL (1920x1080@60Hz)
Intel HD Graphics (MSI)
Storage
931GB Seagate ST1000DM003-1ER162 ATA Device (SATA ) 28 °C
Optical Drives
No optical disk drives detected
Audio
High Definition Audio Device

Right Now I am using Intel HD Graphics since the GPU wouldn't let me boot.

I think the parts are 2-3 years old, PSU is Power Man IP-S400T7-0, now what happens is it does not boot, post and lets me use windows 10.
Before it was 140fps average on Fortnite before it stopped working. So there was no performance issues.

rn i am using integrated gpu