If you aren't in the habit of keeping this kind of information, don't worry too much: Windows keeps a track of your login and logout in one of its Event Logs. Getting that information is fairly easy, if you know what you're looking for. Otherwise its like the proverbial needle in the haystack.
The script outputs into an Excel spreadsheet, the date of each logon in a separate column containing time of logon and logoff. Please note that the script was designed to query someone else's machine, and will likely need modification if you are trying to get your own data out of your own event log.
Here's the code.
As is often the case in my scripts, the preamble loads external code libraries. The former is a the standard library and the latter (see the end of the posting) a symbol table class, based on the Scripting.Dictionary object.
Next comes code to split up the event log's timestamp, followed by the routine to store logon date and logon and logoff times into spreadsheet cells.
Next comes the variable declarations. In retrospect the variables sComputer and sUser could have been Const rather than Dim. For that matter they could have been taken from the command line. Note the double backslash in the uUser variable: this is needed for where it occurs in the WMI call.
This is the core of the script: pointing WMI at sComputer and executing an SQL query against Win32_NTLogEvent. It asks for everything from the 'Security' Logfile where the EventCode matches a logon or a logoff and where the User matches sUser.
Then the script starts to do things with the list of events now stored in cEvents. First a Dictionary is loaded with logons as (zero, comma, TimeSplit of datestamp) and logoffs as (one, comma, TimeSplit of datestamp). The reason for this is that there may be more than one logon and logoff event for a given user during a working day. By storing the logon and logoff times in this way, the first "0" reference can be assumed to be the first logon off the day, and the last "1" can be assumed to be the last logoff of the day.
From the Dictionary wrapper class the keys are extracted. A check is put in here to make sure that there are records to be reported.
Next comes the Excel interactions. The ExcelStart and ExcelNewSheet macros are listed at the bottom of this posting.
What follows is the guts of the Excel reporting. Despite the possibility of incorrect recording, the assumption is that the report will contain the first logon and the last logoff. If a logon occurs after the last logoff, it is discarded. The script is unable to cope with the situation where someone logs on today and logs off tomorrow.
Note that a check is made not to report more dates than MAX_INSTANCE, a limit that has not yet been encountered. AMax and AMin are listed at the bottom of the posting.
Excel is left running with the results of the report. It's up to the user to save it, print it or whatever. To finish, the macros ExcelStart, ExcelNewSheet, AMax and AMin, and the ClassSymTab class as promised.