Snap Deploy and Lenovo Thinkcentre M series

I have the latest version of Snap Deploy and am trying to get a group of Lenovo Thinkcentre M series desktops to connect to the server but to no avail. They try to boot to the PXE server but eventually time out and continue booting their OS. The other problem that I have consequently found is that I am unable to create boot media, anything I create is blank. I have also tried the option of creating a PE bootable disk but the system refuses to boot from this. On another network I have a Microsoft PXE deployment server that these PC's connect to with no problem and I also have other Lenovo PC's that connect to Snap Deploy with no problem. Any help would be much appreciated. Thanks.