Two or three questions, maybe unrelated:
1. Did you use Norton and fully removed it? Which other Symantec products did you use?
2. Is the two letters at right of the clock a normal thing on your language or not?
3. Any useful information into Control Panel > Administrative Tools > Events, specially 'Errors'?
Could that check and uncheck of the detail info solved the problem?
I don't think so... maybe other 'hidden' action that you've done or the computer take...