Keeps asking for reboot

I installed the WB6 demo and rebooted, however it asked for a reboot again. After the second, it still asked for a reboot. I even disabled my anti-virus and firewall, as it suggested, but that didn't work. So, I uninstalled, using RevoUninstall, and tried installing it in Safe Mode, but got the same results. So, I uninstalled that and tried installing a 5.5 demo I found on the internet, but still got the same problem. I've searched all over the internet, but all results have no solution. I had a feeling it's something to do with WbSrv.dll, as, even when I've uninstalled it, it stays behind and when I try and delete it it says that it's being used. So I tried installing WB to a different folder, but still, the same results. What can I do?