sihost.exe is a program which is most likely NOT a virus or malware. So, if sihost.exe is on your PC, it is most likely ok, and will NOT be a cause for concern. Even if your system is virus-free, it is still recommended to purchase a good antivirus with a good detection rate, in order to defend your system against potential security problems.
Usually, this program is stored in C:\WINDOWS\System32\sihost.exe.
The MD5 checksum for this file is 6f962a71468981b9606f6805badabf25.
This program does NOT operate as a Windows service. This is usually a good sign.
sihost.exe seems to have something to do with Windows SFC (System File Checker) or Windows File Protection.
This is a 64-bit executable. It runs using the full capacity of modern CPUs.
This application does NOT have visible windows. This is most likely a bad sign.
sihost.exe has a digital signature. Nowadays the large majority of clean programs are digitally signed.
The digital signature found in sihost.exe checks out perfectly. This is very good.
Digital certificate name: Microsoft Windows
Certificate's issuer name: Microsoft Windows Production PCA 2011
This executable does NOT have an uninstall command set up in registry.