Microsoft has “officially” discontinued support for MSDOS under virtual PC, which makes it difficult for us to enjoy our old DOS games (like MechWarrior). However, most of the support files for DOS are still included on the VPC additions ISO, and we just need a little tweaking to make it work. I reviewed the “Dos Virtual Machine Additions.vfd” from VPC2004 and came up with the following steps for VPC2007.
1. Create a directory in the root of C: named vmadd
2. Copy cdrom.sys, fshare.exe, idle.com, and mouse.com from the VMAdditions.iso to C:vmadd
3. Edit Autoexec.bat and add the following lines
mscdex.exe /D:IDECD001 /L:E
4. Edit Config.sys by adding the following lines
DEVICE=C:VMADDCDROM.SYS /D:IDECD001 /L:E
Reboot and you should be good to go, the CDROM will be drive letter R, the mouse will work as it always did under DOS (which is poorly), and the shared folders will allow you to map your PC files.
Remember to use the right ALT key to release the mouse.