I am using Windows 2003 server. I am not finding RUN command on start. When I press Windows+R key it is giving the following message.

"This operation has been cancelled due to restrictions in effect on this computer. Please contact your system administrator"

Please help me

In my IE the home page buttons were disabled due to some virus How to enable them

When I am trying to access regedit from Run command it showing error message "Registry editing has been disable by your administrator"

>Three Threads merged as these seem to be related<

They are related. It's a nasty piece of malware/virus that disable many admin functions to protect itself. I recently fixed a computer that had this and had to reinstall the OS, it's nasty! Try doing a full system scan in Safe Mode with your anti-virus program. Failing that try doing a System Restore to a date before the issue showed up.

Sounds a bit like Group Policy and Security Policy restrictions.

Is the server part of a domain? If so, go to a domain controller, and look at the policies affecting the OU's that it's in.
If not, then go to the computer and go to C:\windows\system32, and open gpedit.msc, and secpol.msc. You can find a whole bunch of settings in there, where you shuold be able to enable those things again.