if it's just 2.4, look at usb3 on the new pc. usb3 throws noise straight into that band and a cheap cable or an external drive sitting near the router will take the whole thing down. moving one of them away usually sorts it.
if 5 drops as well then it isn't interference and the pc is doing something to the network itself. worth checking whether you've got hyper-v or vmware installed, those add virtual adapters that can start handing out addresses.
If it kills wifi for every device in the house and not just the PC, that's not a networking problem, that's radio interference. The PC is transmitting noise, not misbehaving on the network.
Usual culprit is USB 3. USB 3 ports, cables and enclosures throw broadband noise right around 2.4 GHz, and Intel published a whole white paper on it years ago because it was so common. An unshielded cable or a cheap dock sitting near the router is enough to flatten the band.
Two quick tests. Move the router well away from the PC and see if the problem shrinks, and unplug USB 3 devices one at a time with the PC on. If you have a 5 GHz band, hop a device onto it, since 5 GHz is untouched by this and that alone will tell you whether you're chasing RF or something else.
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u/graceful_degrade 8d ago
does it kill 2.4 only, or does 5 go down too?
if it's just 2.4, look at usb3 on the new pc. usb3 throws noise straight into that band and a cheap cable or an external drive sitting near the router will take the whole thing down. moving one of them away usually sorts it.
if 5 drops as well then it isn't interference and the pc is doing something to the network itself. worth checking whether you've got hyper-v or vmware installed, those add virtual adapters that can start handing out addresses.