Re: block software
is this for kids or roommates or other people using the computer? I would turn on your guest account and see what they have access to, then pw protect the administrator account so that only you can access that. I don't think there is any way you can block something at a certain time, then have it unblock at a certain time but I'm pretty sure you can remove stuff from the guest account and give selective access through the password protected administrator account if you wish.
When all else fails...Ham Radio!
I still have the same old HP DV9700T laptop I've had for years...still kickin'