we are completely stumped here...can any one help? we have just fitted a new computer to a router we have built. when we run the steppers, they run for 3 seconds then stall to a halt. when we run the machine using same config file but with an older computer, all is fine and the motors run ok. both comp are running win xp. if we de tune the steppers then they contunue to run ok but every 3 seconds they still  get a pulse and now the speed is too slow...any ideas how to fix this one? it is very urgent please!

Run the driver test and see what it looks like, if its bad then try the optomisation steps outlined on the downloads page. Does this new computer have onboard Graphics? If so that is probably your problem, you may get away with disabling the onboard card and fitting an AGP or PCI graphics card. Run the driver test and do the optomisation first though as that may be all you need to do.
Hood

hi hood, thanks for the reply, the driver test ran ok and we had also  already done all of the optimisation tasks as outlined in the downloads page, that didnt make a difference. we have an nvidia graphics card g force 8400gs. could this card be doing it? if so any ideas how to sort it out?
thanks
marc

Possible that the card ould be the problem but doubtful, however make sure you have the correct drivers installed for it.
Check the pulse width is correct for your drives in motor tuning.
Could be the parallel port is just putting out 3.3volts and the old computer is 5v. If thats the case possibly your breakout board is not happy with the 3.3v. If that is the case then you could get a PCI card that puts out 5v or get a breakout that is happy on the lower voltage.

Hood