Comodo System Utilities Registry boot time Defragmentation

Hello Everyone,

I have a question about Comodo System Utilities Boot Time Registry Defragmentation. For some reason after this boot time defragmentation finishes my computer (acer aspire 5100 winVista) just hangs on a black screen. I have to manually trun it off and then when I turn it back on it comes into the boot time scanner again and when it’s done the computer hangs again.

Can anyone help me with this?

Thank you very much in advance for your time and patience.