I'm betting a couple of factors:

1) XP is finally too dead to even consider continuing to use. You can't get by with IE8.

2) Windows 8.1 has mitigated windows 8 problems. This is probably helping a lot of folks through the 7/8 anxiety.

3) Companies not named Apple haven noticed that their laptops are ugly clunky hunks of plastic and are working on ultrabook-form-factor laptops, placing them only half a decade behind Apple.