I upgraded my CPU and now my PC won't display on my monitor

I upgraded from an Intel Pentium CPU G4400 @ 3.30GHz to a Intel Pentium CPU G4560 and now my PC turns on, but won't display anything on my monitor, I have checked that the HDMI cable is plugged in properly and it is, and my monitor also has power because it turns on.

Note: I have put my old CPU back in for now.

My PC specs:

Computer Information:
Manufacturer: Gigabyte Technology Co., Ltd.
Model: To be filled by O.E.M.
Form Factor: Desktop
No Touch Input Detected

Processor Information:
CPU Vendor: GenuineIntel
CPU Brand: Intel(R) Pentium(R) CPU G4400 @ 3.30GHz
CPU Family: 0x6
CPU Model: 0x5e
CPU Stepping: 0x3
CPU Type: 0x0
Speed: 3312 Mhz
2 logical processors
2 physical processors
HyperThreading: Unsupported
FCMOV: Supported
SSE2: Supported
SSE3: Supported
SSSE3: Supported
SSE4a: Unsupported
SSE41: Supported
SSE42: Supported
AES: Supported
AVX: Unsupported
CMPXCHG16B: Supported
LAHF/SAHF: Supported
PrefetchW: Supported

Operating System Version:
Windows 7 (64 bit)
NTFS: Supported
Crypto Provider Codes: Supported 311 0x0 0x0 0x0

Video Card:
Driver: Radeon(TM) RX 460 Graphics
DirectX Driver Name: aticfx32.dll
Driver Version: 22.19.662.4
DirectX Driver Version: 22.19.662.4
Driver Date: 7 20 2017
OpenGL Version: 4.5
Desktop Color Depth: 32 bits per pixel
Monitor Refresh Rate: 60 Hz
DirectX Card: Radeon(TM) RX 460 Graphics
VendorID: 0x1002
DeviceID: 0x67ef
Revision: 0xcf
Number of Monitors: 1
Number of Logical Video Cards: 1
No SLI or Crossfire Detected
Primary Display Resolution: 1920 x 1080
Desktop Resolution: 1920 x 1080
Primary Display Size: 26.65" x 15.00" (30.55" diag)
67.7cm x 38.1cm (77.6cm diag)
Primary Bus Type Not Detected
Primary VRAM Not Detected
Supported MSAA Modes: 2x 4x 8x

Sound card:
Audio device: Realtek Digital Output (Realtek

Memory:
RAM: 16340 Mb

Miscellaneous:
UI Language: English
Media Type: DVD
Total Hard Disk Space Available: 953766 Mb
Largest Free Hard Disk Block: 272353 Mb
OS Install Date: Dec 31 1969
Game Controller: None detected
VR Headset: None detected