Hi,
Follow the steps listed below and check if it helps.
Method: Run the System File Checker scan.
http://support.microsoft.com/kb/929833
Method 2:I would suggest you to check the issue in clean boot.
1. Click Start, type msconfig in the Start Search box, and then press ENTER.
User Account Control permission.
If you are prompted for an administrator password or for a confirmation, type the
password, Or click Continue.
- On the General tab, click Selective Startup.
- Under Selective Startup, click to clear the Load Startup items check box.
- Click the Services tab, click to select the Hide All Microsoft Services check box, and then click Disable All.
- Click OK.
- When you are prompted, click Restart.
- After the computer starts, check whether the problem is resolved.
If the issue is resolved check which third party program is causing the problem, referring the link given below:
http://support.microsoft.com/kb/929135
Reset the computer to start as usual.
After you have finished troubleshooting, follow these steps to reset the computer to start as usual:
Click Start, type msconfig.exe in the Start Search box, and then press ENTER.
If you are prompted for an administrator password or for confirmation, type your password, or click Continue. On the General tab, click the Normal Startup option, and then click OK.
When you are prompted to restart the computer, click Restart.
Method 3:Follow the steps below to fix the issue
****1. Click Start->in start search, type "services.msc" (without quotation marks) in the open box and click OK.
- Double click the service "Windows Update".
- Click on the Log On tab, please ensure the option "Local system account" is selected and the option "Allow service to interact with desktop" is unchecked.
- Check if this service has been enabled on the listed Hardware Profile. If not, please click the Enable button to enable it.
- Click on the tab "General "; make sure the "Startup Type" is "Automatic". Then please click the button "Start" under "Service Status" to start the service.
- Repeat the above steps with the other service: Background Intelligent Transfer Service (BITS)
**Method 4:**I would suggest you to perform a virus scan on your computer.
http://www.microsoft.com/security/scanner/en-us/default.aspx
I would suggest you to provide us the event log information.
http://windows.microsoft.com/en-US/windows-vista/Open-Event-Viewer