If you search for Windows Vista crack to bypass the activation, you will most likely notice that many of them instructs you to install Windows Vista after changing the BIOS date to year 2099, or issue a command to re-arm Windows Vista in year 2099 or whatever year in the future such as 2098, 2090 or 2050. There are generally 2 ways to perform a “2099 trick” or “2099 hack” for Windows Vista:

1. Install Windows Vista in 2099
2. ReArm (reset or extend activation grace period) in 2099

Either way to perform “2099 trick” is equivalent. But why do you need to install or rearm in 2099 or future date? General explanation or reason is that in Windows Vista, there are at least 2 timers that count or keep track on when the remaining time of activation grace period expires. One of the timer counts the 30-day duration from installation of Windows Vista. By installing in year 2099, this timer breaks or is cracked. Thus, Windows Vista will use another timer to keep track and record the actual time you boot into and use Windows Vista by minutes, with countdown starts from 43200 minutes (equal to 30 days) from the time you install the license product key which is changed re-arm or install in 2099, which indirectly extend the activation grace period to more than 30 calendar days if you don’t run Vista system 24 hours a day.

More technical details offered by offlinevista is that Windows Vista probably does a “timer = min(savedtimer, exprdate-curdate, 30days)” at boot to determine grace period time remaining. 2099 trick will make the value of exprdate-curdate high. Beside, you can also check your install date that been captured on stored on Windows Vista, by using the following command in a command prompt:


Search for “Original Install Date”. In you install Windows Vista in year 2099, you will see a very weird or useless install date instead, rendering some SPP timers useless. It’s because 32-bit systems can only store a maximum of 2^31 non-negative seconds (2,147,483,648 seconds or 68 years beginning at 1 Jan 1970, 12:00:00am GMT). The 32nd bit is to differ positive and negative numbers. This means that when the time_t variable count reaches 2147483647 (19 Jan 2038 at 3:14:07am GMT), it will wrap to or continue from -2147483648 count, which is Friday, 13 Dec 1901, 8:45:52pm GMT. However, negative time_t value (which is time before January 1, 1970) is not allowed. In such case, Windows handles that kind of entries as unknown data type, and will switch to use internal Windows timer. This will set the value to 0 which equivalent to 16 Jan 1601 12:00:00am GMT. If you set time to date before 2038 systeminfo will show the correct date.

Steps to perform Install Windows Vista at 2099 Trick

  1. Disconnect from Internet to avoid time auto synchronization.
  2. Set the BIOS date to 2099.
  3. Install Windows Vista. Do not enter any product key or serial number. You should leave the license product key field blank when prompted.
  4. When Windows Vista installation is done, boot into Windows Vista, and set back the date and time to current date and time value from within Windows Vista, by using “date” command or double click on Vista clock.

Steps to perform Rearm Windows Vista at 2099 Trick

  1. Disconnect from Internet to avoid time auto synchronization.
  2. Set the BIOS date to 2099. (This method may cause Windows Vista into RFM (reduced functionality mode)


    Change the date to year 2099 from within Windows Vista, by using “date” command in Command Prompt or Date/Time applet.

  3. If you change the date by using BIOS, restart to boot up into Vista.
  4. If you change the date by using BIOS, but been shown RFM locked out system where everything is impossible to do with just Internet Explorer and activation screen, plus auto logoff, follow these instruction to recover from reduced functionality mode, otherwise, skip to the next step:
    1. Type the following in the address bar of Internet Explorer:file://c:
    2. You will be shown Windows Explorer. Browse or navigate to \Windows\System32 folder.
    3. Find cmd.exe file.
    4. Right click on cmd.exe and select “Run as Administrator”. If UAC prompts for confirmation, click OK.
  5. Rearm Windows Vista by using one of the following commands:

    slmgr -rearm


    cscript slmgr.vbs -rearm


    rundll32 slc.dll,SLReArmWindows

  6. Restart the computer.
  7. Change back the BIOS date to current time.


    Change back the date to current year from within Windows Vista, by using “date” command in Command Prompt or Date/Time applet.

You can change the status of the remaining time left for activation after rearm by using one of the following commands:

slmgr.vbs -dlv


slmgr.vbs -xpr

One myth is that you will always see 43200 minutes left once after you rearm or install Vista in 2099. However, it’s not always the case, as Windows Vista countdown timer is initialized at the end of setup, and by the time you manage to boot up and login into Windows Vista desktop, several minutes would be spent. The only possible way to have 43200 minutes is by using “2099 rearm trick”, although you lesser than 43200 or even 43199 too if you have a slower start.

Disclaimer: This article is for educational and informational purpose only.