Windows Update kept trying to upgrade my graphics card (Intel 945GM in Lenovo X60 tablet) and failing. I tried manually upgrading the driver with ones from both Intel and Lenovo, and neither worked. Here are the steps that solved my problem:

1) Open windows explorer to “c:\Windows\inf\”

2) Right click “INFCACHE.1” and select “Properties”
3) Go to the “Security” tab and click “Edit”
4) Select “Users” and then check “Full control” under the “Allow” column below, then hit “OK”
5) “OK” again
6) Now right click “INFCACHE.1” and “Rename” it to “INFCACHE.1.old”
I also did this for “setupapi.ev1”, “setupapi.ev2”, “setupapi.ev3”, and “drvindex.dat”, but I’m not sure they’re necessary.
7) Try installing your driver again (you might need to restart before doing this, I’m not sure)
If that works it’s probably safe to delete those files you renamed to “.old” (Windows should have made fresh ones, minus the “.old” extension). Apparently that INFCACHE file can get junked up, but Windows doesn’t know to recreate it unless you manually remove (or rename) it.
These links helped me out: