Desktop Turns On but Shows No Signal and the Fan Runs Loud

The loud fan by itself doesn’t identify the failed part. Since there’s no display at startup, the computer may not be completing its initial hardware check. That can come from memory, the graphics card, power connections, or the motherboard, so guessing and repeatedly rebooting probably won’t help. A new prebuilt system should be inspected or replaced by the seller.

Before contacting support, you can try a few safe checks: turn the computer off completely, unplug it for a minute, and make sure the monitor cable is firmly connected at both ends. If you’re using the graphics card, the display cable should normally be plugged into the RTX card rather than the motherboard’s video ports. You can also test another monitor input or cable if one is available. If the fan remains unusually loud and there’s still no image, stop troubleshooting and use the warranty.

Because the PC is only a month old, I’d avoid opening it up or removing components unless the seller’s support team tells you to. Contact the seller or warranty provider and describe the loud fan plus the no-signal message. It could be a loose internal connection or a hardware fault, and warranty service is the safest option.