I'd hate to say this but the log looks extremely clean.
Right lets try and rule out viruses, do you have any anti-virus software installed ?
If not then try to download AVG antivirus, below is a direct link to the file.
AVG Antivirus
Once downloaded try run a scan on your system, if it freezes up then try boot into safe mode and run it from there.
If that fails then I think we could try backing up your harddrive and reloading windows, I will start working on a little step by step document for you.(just in case)