For the past two months, I have had intermittent system freezes at start-up and while running programs. The freeze is corrected by hitting ctrl-alt-delete. When the dialog box appears, I hit cancel and everything is okay. I have run AVAST X2 in safe mode, Malwarbytes' Anti-Malware X2 in safe mode, installed Windows 7 on another hard drive, run WIN Memory and MEMTEST68 (both normal). Disk Checker is normal, Intel's processor check is normal, and I changed RAM and video cards. I also reinstalled Windows 7 on main drive after format. Temps are less than 40 degrees.
You've certainly done a thorough job trying to troubleshoot this. These are the only things I could add: Progressively disable your start-up programs one at a time (use MSCONFIG) and see if anything changes. Check the System event log for suspicious errors. Run the Task Manager, Process tab sorted from the top CPU consumer on down. Size it down to where you can still do other work but also can see the top process. Look to see what the top consumer is next time it freezes.
Also, when it freezes, are you able to use the keypad aside from ctrl-alt-delete? Try pressing the Windows key to see if it responds. If it does, your mouse may be the problem. There could also be a defect in the system PCB (motherboard) that would be almost impossible to detect.
I have an HP PC. I use Vista home premium. I keep getting this code: "USB port not recognized." I have done everything possible to check out each port. The computer says all are working. I have also unplugged all wires and left the computer off for one hour. I need to get this off my screen.
If by all "wires" you mean the power plug, that is a common fix for this problem. If you haven't already, unplug the computer from the wall outlet after shutting down and wait a few minutes before plugging it back in. You can also try uninstalling the USB Controllers from Device Manager. They should automatically reinstall upon rebooting or by entering Device Manager, right-clicking the computer name at the top and choosing Scan for hardware changes.