I assume you mean open the "event viewer", under the "Windows Logs" folder open the "Application" folder and in the "Source" column look at the "Winlogon" entries. All thats ever shown are 2 different event notifications. NO chkdsk logs. (...and I checked a months worth of "Winlogon" entries.)
There should be actual files (*.log or *.txt) located either on the "root" drive or the "Windows" folder that contain the info of what occured during the execution of the CHKDSK command before bootup. At one time it could be found in the "bootex.txt" file, but I can find no such animal in Win7.
In the right-hand panel of the event viewer you should see a panel of "Actions". You want "Save All Events As..." and then select .txt format in the file save dialog. If you only want to save some particular entries, use "Filter Current Log" and "Save Filtered Log File As...".
Sometimes, Windows 7 fails to record log in Event Viewer. I just ran it on a corrupted disk drive for about 3 hours. When the system booted up, I searched Event Viewer for the log but it is not there. I work on PC's regularly and have seen this happen several times on Windows 7.
I am using Windows 7, Pro (64-bit) and found the chkdsk logs in:
Event Viewer > Windows Logs > Application
Sort by 'Source' and look for 'Chkdsk' as the source. The Event Viewer will list each scan. Click on the desired scan to view both system-event information and scan results in the preview pane; if you don't see a preview pane, you can turn it on in the 'View' menu or simply double-click the log entry to open it in a separate window.
You can save it as a text file by clicking the 'Save Selected Events...' action button in the action panel. Then, give the text file a name and use the 'Save as type:' menu to choose 'Text (tab-delimited) (*.txt)'