Error Loading Windows Service Pack 3

I am trying to upgrade an older system to the Windows Service Pack 3 release. I am using Windows Update to load the SP.

When it begins to check my system configuration I get the error message:

Ndis.sys is in use or being used by another program and then I am given the option to retry or cancel. I've searched the Internet and found that Ndis.sys can also act as a virus, but it can just as well be a legitimate windows system file. In either case, I can't get past this point to load SP3.

Can someone help?

I have used the forum so far to run all of the suggested software to clean my system of malware, viruses and spyware.


Windows XP Home Edition SP2
Pentium 4 Processor 3.00 GHz

 

rejavanation, you need to post the logs here
http://forums.majorgeeks.com/forumdisplay.php?f=35
and have the Malware fighters look them over so we know you are clean.

 

Thanks for you response, but I resolved the problem.