Windows 2000 Prof SP4

I have a Dell Inspiron 8000 laptop running w2k prof with sp3. Whenever I try to update it to SP4 a box pops on the screen with the following message.

The c:\arcsetup.exe is open or in use by an application. Close all other applications and then retry.

I have made sure that no applications are open when I run the SP4 update but no luck. The DELL guys couldn’t help me either.

Your help would be much appreciated