you did not mention the time frame during which it happened.
The logs are the "windows logs", come in 5 categories. Administrative events is just a custom view on those.
You can clear the logs, but there is probably no need to do so, as we can easily filter them and then sort/group them if needed.
For now we can probably focus on System events.
From those screens, I can say those kernel related errors could be an issue, do they happen often?
Other than that, of course I'd be curious to know more about the programs you use, including security setup.
I'd be curious to know more about the activities going on when you experience the system freeze.
I can recommend process monitor: Process Monitor
And also, how long have you had windows 7 installed for?
I'll be away for a few hours, hopefully someone can take over, but if you have some free time, might be wise to run some antivirus scans, manual scanners like norman malware cleaner and bitdefender free could be a good start, as well as something like malwarebytes anti-malware and superantispyware and make sure you have a working firewall.
But first step might simply be to make sure there isn't too much stuff in the startup locations and get rid of a few very recently installed applications, if any.
How long you've been using windows 7 for will be important information, as well as whether you've experienced such problems with another os before.