Report just on Windows vms with snapshots

Currently have 'VMs with old snapshots (older than 30 days)' report but since we have linux/unix systems in our SAM monitoring, I would like to isolate this report by just showing Windows based operating systems in this report. Not sure how to go about it.

this is in the query: SELECT vm.Name, vm.GuestState, vm.MemUsage, vm.CpuLoad, vm.OldestSnapshotDate, vm.TotalStorageSizeUsed, vm.SnapshotSummaryCount, vm.PlatformID, vm.Status, vm.DetailsUrl, vm.Host.HostName, vm.Host.Cluster.Name AS ClusterName
FROM Orion.VIM.VirtualMachines vm
WHERE DayDiff(vm.OldestSnapshotDate, getUtcDate()) > 30