When will Windows 7 beta stop working?

I guess Windows 7 beta 1 will stop working at some point (like all the other betas), but does anyone know the date? I hope there's another beta or the full version is released by that time, so I can jump on to the next one without a format

When you installed it and entered your key, it told you then!

You've got until 1st August 2009 - so a good few months yet:

Source : http://www.microsoft.com/windows/win...tructions.aspx

Does anyone know how it will stop working? through updates maybe?

Running winver.exe will tell you when your windows 7 will expire.
I assume Microsoft will continue updates up until that point. I doubt they will carry on the upgdates from after that time.

Once Windows 7 expires, the computer will restart every two hours.