Freezing after ubuntu 20.04 upgrade

I upgraded from ubuntu 18.04 LTS to ubuntu 20.04.1 then my computer suddenly started freezing. It will work for a minute then anything i was doing on the computer will freeze. the mouse cursor can move but i can do anything. I HAVE to USE CTRL-ALT-F1 THEN LOGIN THEN, IT WILL WORK FOR A MINUTE then freeze again . my cpu is amd 4300 and graphics is ati 5300 series. Can somebody help me please.

@heynnema

my computer has

AMD cpu- FX4300 quadcore
ATI Radeon HD 5430
Gigabyte motherboard-GA-970A-DS3P
AMD 970/SB950/rev 1.0

~$ sudo dmidecode -s bios-version

F1

~$ sudo lshw -c memory

  *-firmware                
       description: BIOS
       vendor: American Megatrends Inc.
       physical id: 0
       version: F1
       date: 04/08/2013
       size: 64KiB
       capacity: 4MiB
       capabilities: pci upgrade shadowing cdboot bootselect socketedrom edd int13floppy1200 int13floppy720 int13floppy2880 int5printscreen int9keyboard int14serial int17printer acpi usb biosbootspecification uefi
  *-cache:0
       description: L1 cache
       physical id: 5
       slot: L1-Cache
       size: 192KiB
       capacity: 192KiB
       clock: 1GHz (1.0ns)
       capabilities: pipeline-burst internal write-back unified
       configuration: level=1
  *-cache:1
       description: L2 cache
       physical id: 6
       slot: L2-Cache
       size: 4MiB
       capacity: 4MiB
       clock: 1GHz (1.0ns)
       capabilities: pipeline-burst internal write-back unified
       configuration: level=2
  *-cache:2
       description: L3 cache
       physical id: 7
       slot: L3-Cache
       size: 4MiB
       capacity: 4MiB
       clock: 1GHz (1.0ns)
       capabilities: pipeline-burst internal write-back unified
       configuration: level=3
  *-memory
       description: System Memory
       physical id: 2c
       slot: System board or motherboard
       size: 8GiB
     *-bank:0
          description: DIMM Synchronous [empty]
          product: Dimm0_PartNum
          vendor: Dimm0_Manufacturer
          physical id: 0
          serial: Dimm0_SerNum
          slot: Node0_Dimm0
     *-bank:1
          description: DIMM DDR3 Synchronous Unbuffered (Unregistered) 800 MHz (1.2 ns)
          product: BLS8G3D1609DS
          vendor: Undefined
          physical id: 1
          serial: A5063A4D
          slot: Node0_Dimm1
          size: 8GiB
          width: 64 bits
          clock: 800MHz (1.2ns)
     *-bank:2
          description: DIMM Synchronous [empty]
          product: Dimm2_PartNum
          vendor: Dimm2_Manufacturer
          physical id: 2
          serial: Dimm2_SerNum
          slot: Node0_Dimm2
     *-bank:3
          description: DIMM Synchronous [empty]
          product: Dimm3_PartNum
          vendor: Dimm3_Manufacturer
          physical id: 3
          serial: Dimm3_SerNum
          slot: Node0_Dimm3