Question: I would like to know whether there is any way I can run an absolutely unknown executable file without being hacked even if the file contains a lot of malicious code. Is there any program in which I can run it without putting myself in any risk?

Answer: 
Another thing to consider, is whether this program will attempt to replicate, leak data, or do other damage over the network. To prevent that from occurring, I would recommend using a Virtual Machine. Take care to remove host access (or sometimes called host / guest file sharing) and remove any virtual networking interfaces before running the program in the VM. Good VM hypervisors should give reasonable protection to the data and hardware on the VM host, but if you're really worried about that, consider running it in a VM on dedicated, non-networked VM host.

Also check out [sandboxie](http://www.sandboxie.com/), it's basically intended for running untrusted programs in isolation. This does not prevent the program from making network connections though.
You cannot.

If you use OS-level virtualization solution (sandboxes, containers, selinux), the malware can use local privilege escalation exploit.
If you use hardware virtualization the malware can exploit vulnerabilities in the hypervisor (and other underlying software including OS, bios and firmwares (a lot of devices have firmwares flashable, this allow creation of extremely persistent rootkits)) and fault injection like RowHammer.
If you use an emulator, the malware can try to exploit a vulnerability in the emulator.

So you need a separate physical machine and if you need to analyse binaries automatically you need the software on the analysing machine to be not vulnerable.

Now forget everything written above because it is not a real life scenario (unless you are high-value target for intellegence agencies). A hardware virtualization solution (for example QubesOS) should be enough, if you cut it from devices (no OpenGL passthrough, no PCI passthrough, no USB passthrough, no access to storage, etc ...)