Acronis offers three ways for you to boot the computer.
You can press <F11> when prompted during boot-up (just after the BIOS screen and before Windows starts). This takes you into the boot procedure in the Acronis Secure Zone on your hard drive.
You can boot from the Acronis True Image software CD (that you say you've lost).
You can boot from an Acronis Rescue CD - if you made one.
If you have no access to any of these, then I'm afraid you appear to be up a blind alley.
Just one other thought: you say that you're getting a message that reads "Windows could not start from the selected boot disk". Could it be that you have, in fact, carried out a successful restore with Acronis, but that you have not set the BIOS to boot Windows from your C: drive?