system tool/securepccleaner attack won't stop

I have suddenly encountered a virus that begins by opening popupscanner for something called system tools. When I saved the scanner results I read through it and found a reference to the securepccleaner virus. It starts at bootup with the message that I have many problems (virus, trojan, etc) the program/scanner starts automatically and then prevents me from opening anything else with the warning that whatever I try is infected. Booted into safemode and tried finding it in Task mgr processes but wasn't there. Searched the registry and didn't find it there either. It is somewhere but I haven't found it yet. Tried Super spyware and the scan didn't turn up anything - junk. Tried Spybot S&D and it found a win32 thing threat in red and eliminated it. I thought that was where it may have been hidden. Nope! The System Tool scanner poppped up again on reboot and is not allowing me to easily open any other program or file. It takes over the desktop with it's warning and wants me to buy the program to fix this.
I am stumped. Hoping for some help and/or suggestions.

Sounds like malware. I would try malwarebytes Malwarebytes . And ask in the malwarebytes forum and they will gladly help you clean up your system(no charge). And if you want to buy, it's only $24.95 one time charge and it works great.

For all the answers - correct and big thanks. First did Rkill and then Malwarebytes and it did finally disappear. You do need the further information after Malware finishes to delete and change the Hosts under Win/win32/drivers/etc. The exact change is in the instructions and it finishes the process. Thanks for answering. Hope it helps others.