Maybe you could switch to another browser, if it's just your browser that's affected and not the OS.

Thanks guys, for your advice.
I don't have to worry about backing up. That is done regularly. It's the OS that has me worried. I bought the computer about two years ago and there were no OS disks supplied by the company that btw has gone bankrupt since. So I think I'll have to buy a new OS, possibly MS7.
I'll wait for a relative to come and help me in the operation.
There are two intruders on my PC, both rather harmless: Searchnu.com/406 and Whitesmoke.
They are annoying though and the performance of the PC is markedly lower.
The source probably is ilivid, so I'd like to warn everybody: stay away from that obnoxious software.
I'll carry on for the time being. Everything still works, except Google translator. I hope to restore that in due course.

Thanks. I'll keep that in mind when my distant cousin comes.
I have meanwhile disabled one of the two trojans. I can tell it is still there, but it isn't interfering any more. That was the program 'conduit' within Whitesmoke.
I have made sure that both trojans are not a virus. A search on the internet confirmed that.
So in the end I am not as handicapped as I thought I was.
I may keep using the PC as it is now, until I have saved up enough to buy me a Mac. That machine has been on my wishlist for a long time.

YoungArthur wrote on 21. Nov 2012 at 09:37:

Each time when I wanted to use my browser it appeared to have been bypassed by a program called searchnu.com/406.
I investigated the culprit and all symptoms were there: extra entries in my search operations, random ads popping up. Most sites offering help told me that you have to be a wizard like Harry if you wanted to get rid of it. A change of browser would not help, I was assured. I managed to remove the most annoying symptoms and decided that I could live with the remnants.
Since then a second intruder manifested itself: a toolbar that I never installed myself. It could easily be identified as 'Whitesmoke'. Again, it was documented in many helpful websites as a benevolent trojan.
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All in all enough for me to want to make a new start by reformatting my PC. I hesitate to do so and in fact, I couldn't do it myself. I need Harry's help.
It isn't that urgent though. I might consider buying another PC and start from scratch. My present laptop will still be usable for any purpose and as long as I don't connect it to the internet, it will by a fine machine.
Whichever solution I choose, I might be offline for a little while. I hope that my friends at BA won't even notice the transition!