you should try reinstalling while in a Clean Boot using these steps from this article,
http://support.microsoft.com/kb/929135.
Step 1: Perform a clean boot
Note If the
computer is connected to a network, network policy settings may prevent
you from following these steps. We strongly recommend that you do not
use the System Configuration utility to modify the advanced boot
options on the computer unless a Microsoft support engineer directs you
to do this. Doing this may make the computer unusable.
- Log on to the computer by using an account that has administrator rights.
- Click Start, type msconfig.exe in the Start Search box, and then press ENTER to start the System Configuration Utility.
If you are prompted for an administrator password or for confirmation, type your password, or click
Continue.
- On the General tab, click Selective Startup, and then click to clear the
Load startup items check box. (The Use Original Boot.ini check box is unavailable.)
- On the Services tab, click to select the Hide all Microsoft services check box, and then click
Disable all.
Note Following this step lets Microsoft services
continue to run. These services include Networking, Plug and Play,
Event Logging, Error Reporting, and other services. If you disable
these services, you may permanently delete all restore points. Do not
do this if you want to use the System Restore utility together with
existing restore points.
- Click OK, and then click Restart.
I hope this information is helpful.