XP T400 freezes when left unused- roll back graphic drivers?

A few months ago I noticed that instead of 8 hours on my nine cell battery I was getting around 4-5. I read that updating the graphics drivers would help.

Since around then (could be a coincidence), whenever I've left my computer unused for more than about 10 minutes it freezes and forces me to poweroff by holding down the power button. As a result my hard drive is making noise and beginning to fail (PC doctor SMART short self test failed, bios HD test failed).

Lenovo told me I could solve this problem by updating the power management software and turning off the option that allows the Intel 82567LM Gigabit Network Connection to bring the computer out of standby. This has not worked. However it does seem to be related to the internet - yesterday I left it on for a while with the wireless switched off and it did not freeze.

What should I do?

I am tempted to roll back the graphics drivers as that seems to be about the time the problems began. But I am not sure how to do that. Do I need to do it in both discrete and integrated modes?

Any help would really be appreciated. I am afraid my HD can't handle too many more of these forced power downs.

 

Are the chipset drivers installed?

Tried reinstalling Windows and see if it helps.

 

Sorry, what are the chipset drivers?

I am trying to hold off reinstalling windows as long as possible because the discs with my programs I need are in another country and I won't get them for a while.

 

Anyone else having problems with their T400 freezing after being left unused?