Your AMD HD 5450 is a very old Legacy GPU card with no AMD Driver updates.
You have a choice between 2 AMD Drivers that you can download from here: https://www.amd.com/en/support/graphics/amd-radeon-hd/ati-radeon-hd-5000-series/ati-radeon-hd-5450
1- WHQL 2015
2- BETA 2016.
There are no Windows 11 drivers so if you have Windows 11 installed and the Windows 10 driver doesn't work then you would need to upgrade the GPU card or see if Dell has any drivers for your GPU card.
NOTE: Even without any drivers installed you should have Video image because Windows automatically installs its MS Basic Display Adapter.
Do you have your Monitor's cable connected to the Motherboard or to the GPU card? It needs to be connected to the GPU Card to get any image.
If no image then connected it to the Motherboard and see if you get any video image from your Intel integrated graphics. If you do, go to Device Manager under "Display" and see if your HD 5450 is showing.
EDIT: According to a PSU Website your HD 5450 requires a minimum PSU rated at 330 watts or higher:
Your Dell Inspiron 3268 seems to come with a PSU rated at 240 Watts according to this Dell Thread: https://www.dell.com/community/Inspiron-Desktops/Inspiron-3268-GPU-PSU-Upgrade-Dimensions/td-p/75623...
If your DELL PC has a Service Tag just enter it on Dell support page and download the drivers directly from them.
Good luck
