sihost.exe is a program which is probably NOT a virus. So, if sihost.exe is on your laptop or desktop computer, it is probably ok, and will NOT be a cause for concern. Even if your system is clean, it is still recommended to purchase a good antivirus with a good detection rate, in order to yourself your PC against viruses and malware.
Usually, this application is found in C:\Windows\System32\sihost.exe.
The MD5 fingerprint for this program is 1cd2f4a74ad6ac2de5ecf8bb9f12c723.
This program does NOT run as a Windows service. This is usually a good sign.
sihost.exe seems to use the functions of Windows SFC (System File Checker) or Windows File Protection.
64-bit code has been detected. This exe can put to good use the full power of a modern PC processor.
sihost.exe has a digital signature. Today the large majority of clean software applications are digitally signed.
The digital signature extracted from sihost.exe verifies as ok. This is excellent.
Digital certificate name: Microsoft Windows
Certificate's issuer name: Microsoft Windows Production PCA 2011
This application does NOT have an uninstall routine stored in registry.