Why my laptop cant go to sleep mode?

Question

My Acer Aspire 4920g laptop is havin this problem...it cant be put to Sleep mode when it's plugged in to power supply [without battery attached]. When i click Sleep button, the screen goes black for a moment, then the welcome screen appears...

However, when it's on battery, the Sleep mode works just as normal...And anyway, I'm using Windows Vista Home Premium..

Please help me...thanks really a lot...

Answer 1

When your computer is put to sleep, the charging is halted, and re-charges, and because you may have somehow changed the power options, the charging is causing your computer to wake up.

I'm sorry, but I am not completely sure how to fix this though, but you now know that charging is causing your computer to wake up.