Anyone using Windows 7 may experience error 651 problems. This is caused whenever you are trying to connect using a PPPoE connection. The error reports that you will be unable to connect because of a problem with the modem.
Sometimes this would not be a problem with XP or Vista but the problem is only experienced by Windows 7 users.
Bug
This is because the problem is a very well known bug which affects computers running Windows 7. There is currently a lot of effort being put into correcting this. However, there is a workaround which you can use to make your computer easier to use straight away.
Workaround
The easiest workaround is to download a new copy of raspppoe.sys from the internet or another computer. It's important that this is from a vista computer because it will be compatible and doesn't suffer from this bug. Rename the original raspppoe.sys file which is found in c:windowssystem32drivers and then copy the new one in place. Then restart your computer to see if the windows 7 error 651 has been fixed.
Registry Repair
If all the above doesn't work and the problem repeats, the best way to fix it is by cleaning up the registry from errors and invalid entries. The registry is the where Windows 7 keeps its most important data. Any error or invalid entry in the registry can cause serious damage to your computer.
In order to fix and avoid those registry errors you should use a registry cleaner. a registry cleaner is a software which is designed to find all the problems in the registry and fix them. Cleaning the registry will stop error 651 in Windows 7 and will also improve your computer performance.