My problem starts with the Yamaha YMF724F-V. I've had the YMF724F-V for at least 10 years and have had no problems with it. I recently had the opportunity to upgrade to the YMF754-V (second-hand not brand new) and even organised myself a decent 4.1 speaker set. My problem comes in that I originally used the YMF754-V with the drivers for the YMF724F-V as a 2.1 system instead of a 4.1 seeing as I didn't have internet access to download the correct drivers for the YMF754-V and no matter what I tried I couldn't get my rear speakers to work. Eventually I got the correct drivers for the YMF754-V directly from Yamaha's site. I installed the drivers but my sound didn't want to work. I checked my sound controls in control panel but everything was disabled, after seeing this I went into device manager but my whole device manager was blank. I've tried uninstalling the old YMF724F-V drivers and installing the YMF754-V drivers but same problem. I've tried deleting the drivers for the YMF724F-V and then installing the other drivers but same problem. I even tried deleting everything Yamaha out of my registry but still the same problem occurs. Everytime this happens I'm forced to use a system restore. Anyone got any ideas?