Can't run the Registry Editor?

[Mark]

When I click Start>Run>regedit it doesn't run, can you tell me how to fix it?

pls help 

[THT]

1. First of all  run complete scan for viruses and malware.

2. Try the following:
Click Start -> Run -> type cmd and press Enter.
Once the command prompt window opens type sfc /scannow and press Enter. If you have corrupt or missing Windows files you'll need your Windows CD in order to fix them.

hope that helps