How do you diagnose a computer when speed or performance has slowed?

Answer 1

Well first look at the processor and processor speed! Most modern computer will have >2ghz of processor power and/or a multi core processor. If you are spending more than several minutes for your computer to boot up, I would consider it slow.

Answer 2

When a computer has slowed, it is typically a software problem. The usual culprits for a slower system are these:

1. Spyware

2. Viruses

3. Excessive startup programs loading

4. Heavy drive fragmentation (mechanical) or SSD drive needs TRIMMED.

5. Early sign of hard drive failure - the OS may start accessing the drive in PIO mode.

6. A user may have changed some settings

7. One or more drivers might have become corrupted or uninstalled.

8. Your most used program has slowed, such as too many open browser tabs.

9. CMOS corruption or weak CMOS battery losing more optimal settings.

If you suspect the hard drive, you could try a hard drive testing utility, and preferably the one written by the drive's manufacturer. If the drive is acting flaky, then you will want to backup your data immediately. You might have to reinstall Windows on a new drive. If you manage to move the same installation to another drive, then you would want to find a utility to reset the UDMA mode of the drive in the system registry. Windows might have slowed the port that the drive is plugged into.

Then you should remove clutter and empty the recycle bins. Then run various spyware scanners, hijacker scanners, and antivirus programs. If you find and remove virus infections, you should disable and reenable your System Recovery (or System Protection) to dump the recovery data, and create a new recovery point. That way, you won't accidentally reinstall the viruses later.

Then use utilities to check what you have running on startup. Autoruns is a good program for that, but you must not uncheck or delete anything unless you have a clear reason for doing so. If nothing else, just check your Add/Remove programs (or Programs & Features) section in the Control Panel. If there is anything unfamiliar or things you no longer want, you can remove them.

Then you might want to check your drivers. If things are still slow or things have stopped working (no sound, monitor won't enter certain modes, some ports don't work, etc.), then it won't hurt to reinstall the drivers. With video drivers, you sometimes have to remove the current one before updating. Generally, it is best to go to the manufacter's website for each component you wish to update to get the latest drivers.

You should also double check any optimizations you had applied before. If you get CMOS errors, you should check the CMOS settings. If the settings keep getting lost, you may need to replace the CMOS battery. For instance, maybe the hyperthreading setting is disabled, or any custom RAM settings were lost. Other places to check would be the hardware manager page that is in System in the Control Panel, particularly the hard drive and network adapter pages, and the video card's settings utility. In the video utility, you could disable the v-blank syncing or lower some of the quality settings if you want. You can also disable the theming from the control panel and set things to maximum performance. Another place to check would be your power settings and power profiles. If you are using a desktop, you don't need to disable or slow things to conserve power.

One final thing to do would be to defragment the hard drive if it is mechanical, or run the TRIM command if you have a SSD drive that makes use of that feature.