From this mass of infections, i'm not sure if you have a virus or male-ware but we can try to cover both bases.
Just to be clear first and foremost. I'm not a regular technician on this forum, but this may be able to help.
If you have a secondary computer to download programs through put them on a flash drive and transfer them
First you should download rkill from a known good source.
While downloading just to be safe, you may want to rename the files from something other than rkill.http://download.bleepingcomputer.com/grinler/rkill.comhttp://download.bleepingcomputer.com/grinler/rkill.exehttp://download.bleepingcomputer.com/grinler/rkill.pifhttp://download.bleepingcomputer.com/grinler/rkill.scr
You will also want to download malewarebytes from a known good source
I would just use http://www.malwarebytes.org/
Try running rkill a few times, a dos box should pop up saying it is terminating known malware processes.
If the exe does not work, try the com version.
Once rkill successfully runs, a notepad file should open up with what it stopped.
If rkill is able to run, the computer should be in a much better state and should not be shutting down on its own
Now, don't restart the computer.
Remove malewarebytes if its installed, and reinstall it.
Update to the latest definitions.
To be on the safe side i would suggest running a full system scan.
Any entires it finds, remove them.
At this time your computer should be rid of Security tool kit.
If your internet is not working, navigate to Internet explorer -> Internet Options-> Connections tab -> Lan Settings-> uncheck use a proxy server
At this time, i would be concerned about the validity of your mcafee. Update the definitions and try a scan.
If your really paranoid, I would consider running an online virus scannerhttp://www.pandasecurity.com/homeusers/solutions/activescan/
Hope this helps, and i'll try to check back here to see if its resolved.
Mods: didn't mean to step on anyone's toes, if it is not alright that i posted instructions. Tell me and i will willingly remove them.
I can only help.. If i know what the problem is.
we never have time to do things right, but we always have time to do them again