I have an Acer 5110 Laptop cannot get it to boot. It goes to the windows XP logo with the bar underneath and then just stops. I tried to go to last known good configuration but did the same and all of the other safe mode options all stop after it gets to the mup.sys file. Tried doing a repair but it will only get to the screen that says starting windows, you know right before you press enter to install or r to repair or f3 to quit. It will not go any further. Changed out the memory, same problem. Tried another power supply with and without the battery same problem. Was able to install new HDD with no problems installed services packs and all drivers except for the USB driver and all works well. Once I install USB drivers Laptop will freeze and when I try to restart it will do as previously stated above and not boot. Any suggestions?