My HP computer has started opening up a temporary desktop only meant for repairing damage or calling sys admin to say "help" -- why and how to get it to stop?

It started in the past few weeks, while I’ve been working intensively to get my new website ready. It was so disturbing that I downloaded Malwarebytes because the Windows 7 security is so invisible I don’t even know how to make it scan. mbam found 4 tojans, possibly all stemming from a recent visit to German site www.preispiraten.de—since this was found preispiraten3ie.exe [marked trojan].

But instead of fixing it by getting rid of the 4 baddies—now the provisional desktop starts up EVERY time! What is next? A registry scan and repair? I’ve been using the windows 7 security so long I don’t even know which reg and disk ccleaners are best . . .

Geek advice please!!!