790 network is generic

you have rootkit  malware and winsock virus

Thanks for the reply. I start scanning for it but there was no threat found. I use windows defender and malwarebytes.

Clean install with the driver cab file and its working.

Having defender and malware bytes means nothing.

If it did there would be no reason to update signatures every hour.

there are several rootkits out there right now that specifically target Malwarebytes' and Defender and prevent removal.

clean install on an unifected drive will likely work immediately.

Oh i see. I'll try it and tell you what will happen

Hey I'm back still doesn't work. Tried fresh install windows and use the cab drivers still doesn't work. Tried also using a different drive still it doesn't work. I followed this step https://www.dell.com/support/article/en-ph/sln209380/how-to-configure-driver-installation-from-cab-file-s-in-windows-vista-7-8-and-windows-server-2008-2012?lang=en

And this one too https://www.dell.com/community/Enterprise-Client/Is-it-possible-to-install-these-CAB-driver-packages-manually/td-p/4175839

When installing the cab drivers.

Is using a network card will work ? Because I'm thinking of getting one if the onboard lan don't work anymore but I think it will not work either because I got this gt430 the fans spins but when I plug the vga there it doesn't display anything. I know that the network and graphics card doesn't use the same pci slot. That is why i'm still thinking of getting a network card the 790 I have is a MT.

use the cab drivers is not a water chicken install.

You cannot point to a cab file and have drivers installed.

There are no win10 drivers for the 790.

what you do is clean install

then download the win7 cab file.

https://downloads.dell.com/FOLDER01834206M/1/790-win7-A08-34RKD.CAB

then install 7 zip

https://www.7-zip.org/download.html

then move the cab file to MY documents folder

Once there you right click on the cab file with 7zip and say EXTRACT here.

Then you go into device manager and tell it to scan for new hardware and update drivers FROM MY PC not from the internet.

75w card isnt supported with the stock tower power supply.

Use onboard vga to clean install and install all the drivers.

Recommended card for this model is 40W GT1030 LOW PROFILE from MSI

https://www.dell.com/en-us/work/shop/accessories/apd/aa362018

The official DELL GT1030 is 8CCF1

(this is not necessary but it does work)

https://www.ebay.com/itm/8CCF1-Dell-Geforce-GT-1030-2GB-High-Profile-Graphics-Card/312756233837

If you want to use VGA monitor with GT1030 you will need HDMI to VGA adapter.

https://www.amazon.com/ICZI-Gold-Plated-Adapter-Projector-Compatible/dp/B07H2GTR16

EASIEST network is USB WIFI.

https://www.amazon.com/ICZI-Gold-Plated-Adapter-Projector-Compatible/dp/B07H2GTR16

If the GT1030 seems too expensive then I recommend a Radeon HD 5450 passively cooled silent card.

https://www.amazon.com/VisionTek-Radeon-5450-DVI-I-Graphics/dp/B01CN1F1ZM/

Just did what you said still doesn't work. I think I'll just get a network card. I'm thibking this one https://www.amazon.com/TP-Link-1000Mbps-Gigabit-Ethernet-supported/dp/B003CFATNI/ref=mp_s_a_1_3?dchild=1&keywords=tp+link+tg-3468&qid=1593517684&sprefix=tp+link+tg&sr=8-3

And also maybe get a 450watt PSU

I got the radeon hd 5450 when the pc was given to me but when I plugged the vga there it doesn't display anything.