Winsys.exe virus recented infected one of my customer's computers. Two side effects:
1) Regedit is disabled.
2) No Control Panel under the start menu.
Boot to Safe Mode and run SDFix.exe. You can download it from this site:
You may also need to run Hijackthis to remove a regedit disable key. Run Hijackthis and search for regedit. Check off the item to remove it.
This should allow you to run Regedit.
To restore the Control Panel, see the next posting.