|I think your strange error message is causing some confusion. Reference to Windows 8 makes it sound like an operating system (such as Windows 7) and you are using XP. Internet Explorer 8, presumably what it is referring to, is your internet browser. Can you spell out the exact error message you are getting?|
To complicate the issue further, spunist.exe is a Windows service pack uninstall and not related to IE particularly.
There is a vague possibility that you have a virus. It might be worth downloading MalwareBytes freebie, installing it, updating it and running it. Sometimes it can unearth things that your normal AV will miss.
We all live on a ball.