How long is it locking up for bud? Are you leaving it for a bit to see if it recovers or just rebooting after a few mins?
Right click my computer and go to "manage"
In the event viewer go to windows logs, look through the application logs, if there are any serious errors thats where you'll find them.
The other thing to check is in control panel, go to system and security and go to the action center, check for solutions to unreported problems, that one picked up that i'd got a dodgy sata cable, its a big improvement on the old windows error checkers.
Best of luck with it.
One more thing to check to see if its totally locked is the caps lock or num lock key, if the lights go on and off when you're pressing them the machine hasnt totally locked up, if thats the case i'd give it a bit of time to see if it unsticks.
If you can find the hard drive diagnostic software for your drive I'd run that too, hirens boot cd comes with a fair few.
For a mouse i've got a Logitech G5 and its possibly the best mouse i've ever had, you can weight it to whatever your preference is and the buttons are in just the right places, if you do a lot of typing the i'd definitely say go for a natural style keyboard, weird to start with but after a week they're just so damn comfortable its untrue.
If you've got children who are in school it might be worth taking a look at Edubuntu it comes with a massive amount of educational software preinstalled, link below for what is installed from the start with lots more to pick from on the software manager thingy
I'd go for windows 7 because it works, fresh install picks up all your hardware and installs drivers, none of that pesky downloading drivers to get bits running, the only problem i've got with it is some older games refuse to work on it. But to be honest, theyre old and I cant see me playing them anyway.
I'd just get a phone that is a phone, the more complex they become the more they crash/freeze/play up and are liable to be infected, you can already buy an antivirus program for your mobile phone, how insane is that?
I'd try putting the computer into another room that doesnt share the same electrical ring as the bathroom. If it works ok there then you'll know the problem is electrical and nothing to do with any of your settings.