Since EXE files are not running, do the EXEFIX run first to fix up the registry.
If this program does NOT run (you get the same message), then it was the SWEN virus which also corrupts the COM key
Then, download EXEFIX08.INF from the same site above.
To run it, select the file, right mouse, install. (this will correct the EXE problem)
Then, download and run the SWEN Removal tool. It will fix the other registry entries that were modified.
http://www.grisoft.com/us/us_remtext.php?id=swen
If the EXEFIX runs, then the virus was other than SWEN.
After, you should still do a full virus scan with updated definitions to check.
Also, go into the options of your antivirus and change any that say Automatic, to say Ask Me. (or the equivalent).
You always want the AV to tell you what it found (the virus name) and ask you what to do. You can then tell it to attempt to quarantine the virus.
Now, you will always know if you get infected, and also the virus name.