Does it automatically load into the toolbar when you boot up? If so you can always stop it from loading by using Start, Run, msconfig, click on the StartUp tab and looking for it, then disable it by unticking it.
Spyscan and virusburst are indications that you have an infection known as Smitfraud. Smitfraud will use pop ups amoungst other things to inform you that you have been infected by something and that their scanner or program, which you have to pay for, will remove it.These are bogus or sub standard tools and are no better than free tools that you can get to do the same job.
There is a good possibility that the infection has not been completely removed, my advice would be to go to click here and follow the instructions to post a HijackThis log, the people over there will remove the infection and advise on beefing up your security with free programs.
In order to get rid of a program called 'ABetterInternet' I downloaded and paid for this - as it did not identify this I then again downloaded PC Tools 'SpyWare Doctor' which then identified and removed all traces of SPYSCAN - so I lost £29.00. Be aware.
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