Windows 7: Lost external display after upgrading

Apologies if the answer to this has already been posted but I've searched and can't find an answer.

Using standard VGA graphics adapter on an acer aspire 5920G, I've been able to connect my laptop to tv and use dual monitors without a problem for a while. However, I've just upgraded to windows 7 and now find that the second display (i.e. the tv) is no longer identified. I checked for driver updates and it shows this is up to date, but I simply can't locate the external display any longer.

Quite simply it worked fine (connecting directly with HDMI cable) running under vista but has simply stopped under windows 7.

Any suggestions ?

If it worked in vista it should work here. What drivers did you use in vista? they should also work here in win 7. You just need to install it in "compatibility mode".

Ken