Let me start by saying, I've used CC Cleaner for a couple of years, so I don't consider myself a newbie. I've been getting a virtual memory warning, low on RAM, so I ran CC to clean up my computer. I had a couple of tabs open on Chrome so I chose to not clean it during the process. I then ran a registry report, CC showed registry errors, I hit fix and let it do it's thing. After the program closed, chrome seemed to be hung up so I just let my computer go into sleep mode......it still hasn't woken up. I did a hard reset and now my hard drive won't boot. Can't get into safe or BIOS to change boot order.
Registry can't touch bios interaction, it is a Windows only features, while bios runs on your cpu chip.
So it is highly unlikely that ccleaner stops you getting to BIOS.
That said, ccleaner doesn't have a "thing" (by which you mean intended action). Upon analysis, it suggested one or more POSSIBLE registry issues. The program, not being sentient, then requires input from the user; in this instance an ability to read the entries and uncheck items (see my signature for more of an idea what to check off or not) . Upon doing that (or instead of taking that action) the user then must consciously press the clean button where they are AGAIN presented with an ability to go through and reject some of the cleans. Again, without sentience, the program has no intent and thus leaves the conscious decision to you to either read through them or (with the programmer's intent that you had already done so after analysis) press fix all.
Ccleaner did not break the windows part of your computer your anticipation of an outcome not in the design lead to it.
But, again, that isn't relevant at this point as you can't get into BIOS which means there is more in play here than just registry cleaning
Toshiba Satellite L655 series from 2011? let us hope, the hard drive is not over ...
Again this would still allow for bios, as bios is before hard drive mountAlso OP please read (para-quoted from toshiba website)
you must first shut down the laptop completely (not suspended, or in standby mode, or in hibernation mode). If an external keyboard is attached to the laptop (either directly or via a docking station or a port-replicator), disconnect it until you have completed this procedure.*** Use one of the following methods to acess[sIC] the BIOS. F2 key method Turn the computer on. ... press the F2 key to enter Setup, .... The Setup (BIOS) screen will appear. If this method does not work, repeat it, but hold F2. F12 key method Turn the computer on.... press the F12 key, .... Boot options will appear along with the ability to enter Setup. Using the arrow key, scroll down and select . Press Enter. The Setup (BIOS) screen will appear. If this method does not work, repeat it, but hold F12.
A note on the first paragraph: disconnect all peripheral devices, not just keyboards. You can assure full shut down by pressing and holding the power button until you hear everything click/whrrr to a stop.