Have you suddenly problems with Windows 7? – ITavisen.no

Update may be the cause.

Monday, 15. December 2014 – 2:37 p.m.

Microsoft encourages those who have installed Microsoft Windows update KB3004394 (December 9th) to uninstall it.

Creates video curl
update creates namely curl in combination with Nvidia and AMD graphics cards, and can cause the user does not get upgraded their video drivers, including the latest Omega drivers Nvidia and AMD graphics cards.

The problem include Windows 7, Windows Server 2008 R2 and Windows Server 2008 R2.

Not only driver problems
Not only that, but update blocks simply installing other Windows updates.

It is also reported problems with UAC (User Account Control), issues with installing Microsoft Security Essentials and VirtualBox stops working.

Microsoft has withdrawn the update.

Those who were so unfortunate to install it, you can uninstall via Add / Remove Programs. or installing this update that deletes KB3004394 for you.

Source:
AnandTech