Windows 7 – Fixing Computer Restarts Every Hour with Boot Device Not Found Error

Perform a "Clean Boot" if performance returns to normal while clean booted, you know it is a startup program or third party Service that is causing it.

To Boot Clean in Windows 7 and Vista

Accessing the System Configuration Utility

1. Click Start type msconfig in the search box and press Enter

Configure Selective Startup options

1. On the General tab, choose Selective Startup
2. Uncheck Load Startup Items
3. Select the Services tab
4. Check Hide all Microsoft services (important you do this before step 5)
5. Click Disable all
6. Click on OK
7. Click Restart.

If it does perform normally while clean booted you can enable Startup items (Startup Tab) one at a time and restart the PC, do this until performance degrades, then you know which Startup item is causing it, do the same for non Microsoft Services. Leave the problem program or service disabled. Now you can try and determine which 3rd party software is related to the Startup program or service and either update it or uninstall it.

If Clean Boot does not restore performance, restore your system to normal boot by doing the following:

1. Click Start type msconfig in the search box and press Enter
2. On the General tab, choose Normal Startup
3. Click Ok
4. Click Yes, when asked to restart your computer

To detect the source of the problem and to avoid re-installing Windows on faulty hardware, you could test your hardware for potential malfunctions.

For this purpose, download and burn a recovery/diagnostics CD. I personally prefer Hiren's BootCD Here is the download page.

Boot from that CD and try running basic tests, like Memtest86+, which is for RAM, and MHDD, which is for hard drives and can detect bad sectors on your HDD. Notice the tool named Remove Non Present Drivers. Do some preparatory research on the tool you are going to use, be as careful as possible.

Hiren's BootCD offers a number of anti-virus and recovery tools as well. It also includes a Mini Windows XP that you could use to browse files, for example, to see whether renaming a questionable driver so that your Windows doesn't load it on next boot makes any difference, and backup files to a USB stick.

Before getting into troubleshooting, disconnect as many devices as you can. If your motherboard has built-in graphics support, unplug your graphics card and switch your display to the motherboard's video output instead.

Hope you find it helpful.