Log in to the system with administrator rights. Select Start = > Run. Type "msconfig". You will see the window "configure system". On the General tab, select "Selective startup" and uncheck the two options: Process the file System.ini", "Process Win file.ini" "Load startup items". Boot.ini don't do anything. "Load system services" do not disconnect. Click "Apply" and "OK". Then restart the computer. Check for errors.
If the error disappeared, again run the "configure system". Consistently include the option is disabled, and after each turning on one option, restart your computer and see if there are any error again. If there is, then, obviously, it is the last option enabled. If the error persists, that reason is not any of these options, and item 3 can be skipped.
For each option there is a corresponding tab. Open it. There you will see a lot of items are marked. Disable half of them and reboot. Determining which group of items causes an error, split it in half, half off, reboot and so on until until the exact cause of the problem will not be revealed.
If the error is not in the above options, click the Services tab, check "hide all Microsoft services". Click "Disable all" > Apply > OK. Reboot. If the error disappeared, then look for the service that is generating the error, consistently including them.
If the cause is found, check with the specialist what kind of service, file, program startup, for which it is responsible and you can do without it, ie so and leave it off. If it does not, in each case, the actions of their own, but, as a rule, is to replace the damaged file or group of files.
If the cause did not manage to find anything better on their own than trying to look for her, not disabling Microsoft services, may be unpleasant consequences. In this case it is better to consult a good specialist or you decide to reinstall the system.
If errors appear immediately, but after some time (10-30 min), most likely the cause is not in software but in hardware - can overheat a device, or under the influence of thermal deformation somewhere there is a contact. In this case it is necessary to start with checking the hardware.