add arch guest driver install for spice

arch.md

@@ -371,8 +371,16 @@ sudo pacman -S firefox gnome-browser-connector
 
 4. `systemctl enable --now libvirtd`
 
-If you get a blank screen when launching windows VMs check that you've used a secboot
-loader.
+If you get a blank screen when launching a VM check that you've used the correct bios -
+either secboot or not secboot. This is the most common problem.
+
+**Arch Guests**
+
+In order to get drivers for spice you'll need the guest spice drivers:
+
+```bash
+sudo pacman -S qemu-guest-agent spice-vdagent
+```
 
 ### CUPS Printing