DON'T upgrade to 8.1. I repeat, DON'T upgrade to 8.1! Revert back to your original installation. I tried last night to upgrade, it caused a exception_not_handled BSOD. It then kicked me back to my Win 7 drive. I spent the better part of 2 hours restoring my original operating system.
I speak having been from hell and back. Don't touch Windows 8.1.
I am a desktop user, incidentally.
Did you run the upgrade assistant first?
I'm currently running 8 now. What I meant was update, not upgrade. My apologies. The description I provided remains however, since an update caused the same issues.