My brother's PC is locking up on anything that requires UAC elevation - the UI thread continues to run fine but trying to open the control panel or something similar is unresponsive. The prompt never actually shows up.
I ran combofix, the output logs aren't showing anything suspicious. No error messages are cropping up, I can't find anything relevant in the event log. He already tried a system restore to a date before this was happening.
Any ideas?