When something suddenly goes wrong with your system's performance or it fails to boot properly, it may be caused by a recently installed program, update or driver. If using "System Restore" doesn't yield any positive result, Windows "Safe Mode" can be used for troubleshooting the issue. You can boot your system into Safe Mode to see if the issue is still present.
You should first try to determine what recent changes with your system could have caused "Windows" sudden poor performance and reverse them. That is, if you have added any kind of hardware, go to the Control Panel and remove it and uninstall the software package for that device. Reboot when the uninstall completes and if Windows now boots properly, you can be reasonably certain that there was a conflict with that device which needs to be resolved. You might contact the manufacturer for your hardware to see if they are aware of the problem. Chances are, they have already updated a driver file that you need and it wasn't included in the software that came with the device.
If you don't know what caused the problem, you can use the process of elimination to help you resolve it. One option would be to try starting all of the programs you commonly use, including the programs in your Startup folder, one by one, to see if one of them might be the suspect.
If your computer automatically starts in Safe Mode without any prompting, there is a problem with your computer that is preventing Windows from starting normally. You should be able to get things back to normal by selecting one of the Restore Points.
If you have determined the problem is definitely not related to any new software or hardware, then you most likely have a corrupted Registry. If this is the case, you will very likely be better off by performing a fresh install of Windows.How to boot Windows into Safe Mode
Reboot the Windows computer. As the system begins to come back up, you should select the boot drive option (if it is presented) and begin tapping on the F8 key as soon as a black screen appears.Note:The F8 key or "Function 8" key, is located at the top of the keyboard in the row of keys all numbered sequentially
Tap the key repeatedly during the boot up process until you hear a "beep" tone coming from the Central Processing Unit (CPU). You should begin to see the Windows "Advanced Options" menu. Use the up/down arrow keys to select "Safe Mode". Once you have it highlighted, press the "Enter" key.NOTE: If the Windows startup logo appears instead of a black screen, you will need to repeat steps 1 and 2 again. This time, have your finger at the ready and begin tapping sooner. If you dual boot (that is, if you have more than one operating system, or "OS" installed), then you will need only to highlight the OS you want to use the Advanced Boot Option for and then press F8 (no tapping required)
Please be patient as Windows enters Safe Mode. This process takes a bit more time than a normal windows logon session. It could take up to several minutes for the "Safe Mode" desktop to appear.
For most folks, the first visit to Safe Mode is alarming because of it's appearance. It looks quite different from what they expected. This is because only basic services run in Safe Mode. Instead of the normal graphics device driver, Safe Mode uses the standard VGA graphics mode because it's supported by all Windows-compatible video cards. The Windows "Safe Mode" desktop loads up in only 16 colors and at a resolution of 640 x 480.
To return to your normal user mode, just reboot the computer once more and do nothing while the system comes back up. This time, your desktop icons will appear in the arrangement that you had expected.