Tuesday, March 12, 2013

Diagnosis and fix of a “very slow PC” issue

Last September, my primary desktop PC at home (built 2008), running Windows 7 64-bit, started exhibiting a strange set of symptoms: The system would boot up normally, but after that, certain operations, particularly operations needing to read from the hard drive, would take far longer than normal.  For example:

  • Pressing Ctrl+S (Save) from Notepad would take a full minute to display the Save dialog, but the file would save normally after that;
  • Copying files between the two internal hard drives (C: and D:) worked, but took about 20x as long as normal;
  • Applications would sometimes take a very long time (1-2 minutes) to initially start;
  • The game “Torchlight 2” would start, but the “loading” screen would never go away, and the background music looped abnormally, playing the same segment of music over and over again every 5-6 seconds.
  • These problems would all seemingly get worse over time, until I rebooted the PC.

Not having run across an issue like this before, I tried quite a few different troubleshooting steps:

Troubleshooting Step Tried Outcome
Warm boot (restart the PC) No effect
Cold boot (power off and then power on the PC) No effect
Windows System Restore Failed, with a “Failure restoring registry” error
chkdsk /f (“Check disk” utility from the command prompt, with the “fix” parameter) Ran ok and reported no errors for either C: or D:
Ran the Windows built-in RAM diagnostic Ran ok and reported no issues
Virus scan with Microsoft Security Essentials Ran ok and reported no issues
Reseated hard drive SATA cables for both drives No effect

Killed various processes via Task Manager (suspecting a virus?)

No effect

Disconnected the D: drive (the non-boot data drive)

No effect
Booted into Safe Mode No effect – Slowness issue occurred even in Safe Mode

Ran System Restore from Windows bootable CD

Failed, same as when running System Restore from Windows itself

Finally, with other options exhausted, and uncertain whether the root cause might be a software issue with Windows itself, I took the extreme step of “repaving” the PC: Formatting the C: (boot drive) and reinstalling Windows 7.

Doing that actually did initially seem to solve the problem; Windows installed with no issues on the reformatted C: drive, and I was able to reinstall and use all of my applications – for a time.

Unfortunately, in January, the exact same issue suddenly started manifesting again.  The PC would boot ok, and run okay for a few minutes, but then suddenly certain operations like opening new applications or saving files would suddenly start taking far longer than normal.  Further, the problem started getting worse across reboots (as I ran through various troubleshooting steps), eventually to the point where Windows would hang while starting up.

This time, suspecting a hardware problem with the C: drive, I took a troubleshooting step that I hadn’t tried previously: I powered off the PC, disconnected the C: drive, and powered the PC back on.  Although I wouldn’t normally recommend running a PC this way, I actually had an old bootable install of Windows Vista sitting on the D: drive.  With the normal boot disk (C:) disconnected, D: became the boot disk, and the old Vista install booted right up.  (I also physically disconnected the PC’s network card before doing this, not wanting to run afoul of any potential 2013 security issues that a circa-2009 instance of Vista might not be equipped to handle.)

Playing with the Vista install running off the D: drive, I obviously couldn’t really test any non-trivial applications, but the Windows desktop itself was actually usable enough, and exhibited no signs of the slowness issue that the exact same PC configuration, except with the C: drive connected, had been showing.  From this, I tentatively concluded that the issue was a physical problem with the C: hard drive – one that my earlier chkdsk and other diagnostic measures targeted at the hard drive hadn’t picked up for whatever reason.

So I set aside the old, presumably bad, C: drive.  Then – figuring I might as well get a system upgrade out of this whole ordeal! – I ordered a speedy new hard drive, a Crucial m4 128GB 2.5-Inch SATA 6Gb/s Solid State Drive (SSD) (model CT128M4SSD2 - $116 on Amazon.com as of 3/2013), to serve as the new C: boot disk. 

Once the drive arrived, I connected it, once again installed Windows 7, re-installed my applications, and the system is once again running great!  It’s been about 2 months now since the second instance of the “slowness” issues happened, and not only have there been no signs of it returning, but the system now boots faster than ever with the new SSD serving as the boot disk.

I’ll update this post should the slowness issue ever return – but if you don’t see any updates to this post, you can assume that things are still running smoothly -- or that this PC was retired without this issue ever re-occurring!