Hi drj72,
**** Method 1:
You may check if you can install SP1 in a clean boot state. To perform the clean boot follow the step 1 mentioned in the below article and then try installing the update in this clean boot state -
http://support.microsoft.com/kb/929135
If the issue gets resolved check which non-Microsoft service is causing the problem; referring to the article and following other steps.
After you have finished troubleshooting, follow these steps to reset the computer to start as usual:
a. 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.
b. On the General tab, click the Normal Startup option, and then click OK.
c. When you are prompted to restart the computer, click Restart.
Method 2:
You may check if the hard disk is having errors or corrupt sectors, which is causing the issue. I would suggest you to use check disk command and check and repair for any errors on hard disk.
Warning: Microsoft does not recommend interrupting the CHKDSK process. Microsoft does not guarantee the integrity of the disk if the CHKDSK program is interrupted. For safety you can back up your data before using the check disk command if you can.
Use the check disk commands as follows:
a. Click Start.
b. In search window type 'cmd' and ENTER. Right click and select 'Run as administrator'.
c. Type at the command prompt “CHKDSK /P” and press ENTER to scan the disk.
d. Type at the command prompt “CHKDSK C: /F /R” and press ENTER to repair corrupt sectors, if there are any.
NOTE: The root drive has to be C: and the command may schedule a task at the system startup, if it does, then press Y to schedule a task and restart the computer to perform chkdsk.
Once chkdsk completes, boot to the desktop and then check.
You may also refer to the below link for details and check using the steps provided in the article - http://windows.microsoft.com/en-us/windows7/Check-a-drive-for-errors
Hope this helps.
Thanks,
Meghmala – Microsoft Support