having problems with nod32 antivirus program

I woke up this morning and my nod32 told me I had 6 infected files.However it only allowed me to delete 2.I cant even get to the other four.I tried to run a full system scan and everything and it only found one virus.However the AMON that comes with Nod32 says I still have 6 infected files and it only says two was cleaned.How do I fix this problem?
Another problem Im having with NOD32 is when I do a full system scan,I think its not scanning all of the folders.here's some of the error messages I get while its scanning:
C:\pagefile.sys - error opening (Access denied) [4]
C:\WINDOWS\system32\config\system.LOG - error opening (File locked) [4]
C:\WINDOWS\system32\config\software.LOG - error opening (File locked) [4]
C:\WINDOWS\system32\config\default.LOG - error opening (File locked) [4]
C:\WINDOWS\system32\config\SAM.LOG - error opening (File locked) [4]
C:\WINDOWS\system32\config\SECURITY.LOG - error opening (File locked) [4]
C:\WINDOWS\system32\config\SECURITY - error opening (File locked) [4]
C:\WINDOWS\system32\config\SOFTWARE - error opening (File locked) [4]
here's the message that was at the end:[4] File cannot be opened. It may be in use by another application or operating system.

There was more than that but the menu doesnt let me copy and paste all of them so I had to do it one by one.I have no idea why the file is unlocked and I dont know how to unlock it.Im running windows XP.Can somebody please help me fix this problem so I can get these trojans and viruses out of my computer