Problem with sleep and hibernation on the Lenovo Thinkpad T60 in Windows 7

I couldn't find any hints on how to fix this online, so I'm posting my findings here.

Essentially, the problem was that, after installing Windows 7 on my Thinkpad T60, when I closed the lid on the notebook to put it into Sleep mode and then connected it to the AC adapter to charge, after what seemed like 15 minutes or so, it would automatically go from Sleep mode to Hibernate mode, meaning that it would take longer to start back up when I opened the lid. In Windows Vista, it would simply stay in Sleep mode and would only go into Hibernate mode if the battery became dangerously low.

I had installed Lenovo Power Manager (a surprisingly useful tool, as with most Lenovo system tools, and unlike most other vendors' system tools) and wondered if that was the problem. I did uninstall it before fixing this, but I don't think that's what solved the problem.

The problem, I think, was solved as follows:

1. Go to Control Panel, then Hardware and Sound, and then Power Options.
2. On the active plan, click Change plan settings.
3. Click Change advanced power settings.
4. Now, in the Sleep category, under Hibernate after, for a Plugged in state, my configuration had it set to 20 minutes. By setting this to 0 minutes, this is equivalent to "Never", and my problem went away

So, after making these changes, when I put my notebook to sleep and plug it in afterwards, it no longer goes into Hibernate mode automatically, and I don't have to wait for the "Resuming Windows" stage to begin using my notebook again, which is how I prefer it and how I it was configured in default in Vista (or at least in the configuration of Vista as supplied by Lenovo on my notebook).

I am impressed by the depth of power options available on this notebook in Windows 7, though. It gives you fine control over the behaviour in different power states. Lenovo's Power Manager gives even more options, but I may be able to get by without it for what I need.