I'm not sure about Acer, but they may have a partition that has all the files to do a complete install on the existing hard drive. When you go into My Computer do you see C:\ & D:\, or just C:\?
Try doing a system restore prior to the date you removed the fax files. Go to Start/Programs/Accessories/System Tools/System Restore & choose a restore point.
Another option is tf it does have that D:\ partition, reboot the computer, look for something on the screen that allows you to reinstall Windows (like F2 ,F12 or something) and do a restore.
Alan <><