Online, wincnc seems to be up and running.

Their web says 100 kHz max rate, which is a bit slow for new servos, but might be ok if you are not using high-res features, like a milling machine or a cnc tool/cutter grinder or a lathe.

They say it uses an interface card, and the speed of the older cards is unknown.
The card is probably not expensive.
Your have a wincnc license and are a user, so You could probably upgrade the card for not much money.

New brushless ac servos could speed up your acceleration rates by about 5x, and your practical speeds by about 3-5x.
These are not expensive.
Buy ac servos that take mains voltage, around 400-750W.
Ignore the peanut gallery that says you donīt need the power for a laser.

You do, not for movement but for acceleration and deceleration.
Itīs a power of 2 curve - so higher acceleration will result in much higher peak momentary power draw.
And the mains-powered servos donīt need expensive power supplies.

You can use the servos with step/dir controls just like steppers.
Except they are about 10x better in terms of acceleration, speed, and accuracy.

And you can adjust their internal settings so that they donīt need all the high resolution they can deliver, by internally scaling the input pulses your controller can send at 100 kHz.

A modern ac servo of 5000 counts / 3000 rpm needs 50x5000 pulses per sec or 250 kHz.
Just scale it back to 100 kHz internally, since your laser wont need to position to 0.2 microns in any case.
The servos should cost about 400$, give or take, per axis.