when i log on suddenly log off give the solution
[#0005ff]You have a serious malware attack. With luck, this won't affect the Administrator account so try tapping Function 8 when you start the computer and from the menu, select Safe Mode with Networking. If you can log in as Administrator, you need to run all your malware scanners but if you can't get in, please post back for more advice. [/#000ff]
You may need to connect to the system registry using another computer.
When on a network, you need to open a remote registry off the working PC, and connect to the registry of the computer you can't logon to. Sometimes this is caused by a virus/malware, or a remote control program such as PC Anywhere.
This is a good link to a fix for this with some details. If you have issues following what they want you do to, you need to locate a computer savvy friend or a computer shop that can do this.