Sounds like you've been fekked by the fickle finger of ad-ware. Some of them can be a bitch to get rid of... some things to help us help you:
1) Is there a specific URL/domin? summat like coolsearch.web or summat?
2) Download a copy of Spybot (
http://www.safer-networking.org/) and run that against your system. As long as its not the msi thing then it should detect it and remove it.
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