https://pve.proxmox.com/wiki/Migration_of_servers_to_Proxmox_VE
Add mergeide registry file to registry to enable IDE controllers. If the host computer is on a single SATA/ACHI/IDE disk or hardware RAID controller then make an image using Clonezilla. If the host computer is on a fake/software RAID controller (e.g. Perc S100/S300) then make an image using Norton Ghost. Boot computer using WinPE (build by medicat is reliable), load fake RAID controller drivers, use Ghost to image drive to USB drive. Create virtual guest with a WinPE ISO and a temp HDD image big enough to store the Ghost image, be sure to create the guest as a Windows guest. Boot the guest into WinPE and format the temp HDD image NTFS. Shutdown guest and mount temp HDD image using kpartx (provide link). Copy Ghost image and Ghost.exe to temp HDD. Add a new virtual HDD big enought to hold restored Ghost image. Boot guest, use Ghost to restore image to newly create virtual HDD. Shutdown guest, remove temp HDD and WinPE ISO. Boot guest to verify it loads. Once verified shutdown guest, create new virtual HDD, attach is as a SCSI drive, boot guest OS, install virtio drivers. Shutdown guest, remove temp virtual HDD and change controller for main HDD from IDE to SCSI, boot guest.