I've been experiencing a progressively worsening problem with my Windows 7 64 Ultimate system, that is almost 3 years old. No problems until recently and I suspect my C drive is going bad.
It started when windows would go unresponsive just after booting for a while. The mouse showed busy (circle with animated border) but moveable, the task bar and any open windows (usually became unresponsive after opening the first window) were stuck for usually 1+minutes. Then, when it unfroze the startup sound played and ESET smart security icons showed up. At first I thought ESET was blocking things till it finished its startup checks. But, lately the problem has shown up in two other ways: 1) after inputting my password the system goes unresponsive for a few minutes before logging me in. 2) ESET notification displays before the system goes unresponsive. 3) The unresponsiveness starts with at least one window open but doesnt come back. The hard disk is being accessed the whole time. It appears to correspond to C drive access, and a while back I did see event log messages that appeared to be disk related. Once it locks up a power down reset is required and chkdsk runs during the reboot. If the lock up does return I can do things from the D drive like play games and it doesnt seem to have an issue, but things like accessing Outlook (.pst file on the C drive) appear to trigger trouble.