Thanks mugsy, I would be more than happy for you to assist me.
I already have Hijackthis and spybot. I posted a log of HJT at the other forum, and the person told me there was nothing in there of any concern. I also have AVG, Ad-Aware SE and MS antispyware. My system is basically clean, but the advice I'm getting from the other forum, is referring to a possible corruption of the search engine.
With their advice, I logged on as the 'guest user', also as administrator, and tried google from there. It works perfectly. It was also suggested that there may be differences within the privacy and security settings in 'tools'. I compared the 2 users and couldn't find any differences.
I do empty the temp files and history daily, but leave my 'regular' cookies intact. Not entirely sure what you mean by "cache".
I dont know if it would be appropriate to post a HJT log here, or if you needed, maybe I could pm it to you. I do appreciate your time and advice on this mugsy. As a beginner, I'm always in awe of the experts.