Hello,
When I turn on my emachine it says windows boot manager and that to fix the problem i must insert windows installation disc and restart computer. I, of course, do not have this disc. Any ideas appreciated!
If that PC has a recovery partition you can try booting into that. Otherwise, any Windows 7 disc of the same type (Home, Pro, etc) should work to repair your hard drive.
When the eMachines splash screen appears, tap the Alt and F10 keys simultaneously. A screen stating "Starting eMachines eRecovery" should appear.
Now choose to do a recovery from the hidden recovery partition on the hdd or the the recovery DVD's that you should have created when you first got the machine.
If you didn't make the recovery DVD's you will get the chance again if you do a recovery from the hidden partition, best you do it as the hdd can fail at any time and you will have to pay Acer for a new set.
Be aware that either option will wipe all data off the disk, you will loose everything !