When I power on my Windows 7 PC it behaves normally for ~5 minutes, and then I can't open any programs. If I opened something quickly (in the time before the stall) I can still use it. When the computer has stalled in this manner, I am also unable to open new tabs in the usual, direct manner, but if I type a URL in webchat, clicking the generated hyperlink still works. Deleting numerous files in one operation is noticeably impacted as well, but there seems to be no problem with larger, individual files.
It was quite the surprise when everything worked perfectly earlier today without stalling.
I have tried removing unnecessary processes that were running in the background, but the affect was hardly noticeable.
I have previously experienced these symptoms before and corrected them by uninstalling Valve Steam whose constant updates appeared to be responsible for the undesirable behavior.