I'm not sure if this is a windows error or if it is being caused by a virus, but as of today, whenever I click on 'display' in control panel or try to access it by right clicking on desktop the following message appears:
 
rundll
C:\WINDOWS\system32\shell32.dll
access is denied

All I want to do is change my desktop picture's PROPERTIES, but that it is not allowing me to open the display window makes me think the problem is BIGGER than just with opening 'display.'

Please, if anyone knows what I can do to fix this or may know what the problem is, let me know.
ThanksGo Start>Run, type in:
regsvr32 /i shell32.dll (<----watch for "SPACES")
Click OK.
Restart computer.Thanks--
but, it change the problem. Desktop display still wont open. I get the same message.
I even double checked the spaces. What Windows version is it?What do you mean by "it change the problem"?My MISTAKE- I meant that it didnt change the problem.
Its windows XPGo Start>Run, type in:
sfc /scannow
Click OK.
Have Windows CD handy.Now, the error message is showing if I try to access windows clock too, which by the way is incorrect even though I have it set to manual and not web updated. 

What will happen when I run this? If I have to have a windows cd handy, is it going to reboot my computer and erase files?No. It'll only check for integrity of your computer system (Windows) files. Your programs, and data are safe.Ok, I RAN it and when it was done, nothing happened. I restarted the computer. But still the error message and the access denied.  Do you use Comodo firewall?yes I doDisconnect physically from the internet (turn off modem, or router).
Exit Comodo.
See, if you can access "Display".Aha!
Yes, I can then access the display and the clock. What does this mean? Is there a setting in comodo that is keeping me from opening display?No. This is some Comodo glitch.
Do you have the newest Comodo version (open Comodo, go Miscellaneous>About)? It should be 3.0.25.378
If not, update.
If yes, download fresh Comodo copy, disconnect from the internet, uninstall Comodo, install fresh copy, reconnect.