BHO Demon found this how do I remove?

Please advize.

BHO demon found this and I am not sure what to do. I deleted the file but today after rebooting was there again. BHO rates this high risk. I ran spybot s&d but nothing found. also windows defender. Can someone help please? this is the info from BHO Demon:

Also If I post a hijack this log can someone tell if I am allright?

here it is:

Attribute Value
Blocked Load Attempts 1
Clsid {26E45419-7205-4fac-BBFE-174BC7337A79}
Desc Begin2Search
DLL Path C:\WINDOWS\system32\nsn84.dll
Enabled? No - file is missing
Last Load Time 10/22/2007 12:15:20 AM
Load Attempts 1
ProgID optimizer.adssite.1
Status Malware
URL http://sarc.com/avcenter/venc/data/adware.begin2search.html