Hi, my son & I are building a computer using a ROG STRIX B450-F Gaming II motherboard and tried to install the GPU (Zotac Nvidia GEFORCE RTX 3070 Ti) but when we power up the system, the monitor says "no signal" on the HDMI port....Does the motherboard have a "default" PCIE slot that the GPU has to be installed in? Have tried swapping the HDMI cable but that didn't work....Thank you!