A trojan will cause all kinds of problems. Possibly your shutdown issue is
related to it. You do need to get rid of it though before you troubleshoot
any other issues.
I assume you have anti-virus protection however if you do I am uncertain how
you infested your system. You should ensure that your virus definitions are
up-to-date and run a full scan on your system. You can do this from Safe
Mode. After updating the virus definitions for your AV program (generally
you can update through the program itself if it isn't set to automatically
update). Boot to Safe Mode by restarting the computer and immediately begin
tapping the F8 key until you see a screen that gives you a number of start
up options. Use the arrow keys to select Safe Mode and press the Enter Key.
This will start Windows into a state where back ground programs are running.
Trojan's tend to run in the background. Do a full virus scan to see if this
removes the Trojan. When finished restart the computer normally.
If you do not have antivirus software get some now and install it, update it
and run a full scan.
If the Trojan is persistent you may need a lot more help. This tool might
help
http://www.emsisoft.com/en/software/free/
