I had similar problem on my machine:
Can't find script engine "VBScript"
It was a VAIO laptop with stock setup, however I've removed a lot of crappy pre-installed application like McAfee. It appears that the McAfee uninstaller was not able to restore the registry and there was the following entry:
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{B54F3741-5B07-11cf-A4B0-00AA004A55E8}\InprocServer32]
@="C:\\Program Files (x86)\\McAfee\\VirusScan\\scriptsn.dll"
"ThreadingModel"="Both"
Trying to delete the key as suggested by Simplius didn't work because of the permissions restrictions. I had to run regedit, find this key there, right click, Permissions, change owner to Administrator, change permissions to allow Administrator full access to the key.
Then I was able to replace this value with the correct one:
c:\Windows\System32\vbscript.dll
And finally the problem was resolved.