I suspect that my system has been hacked into. I see huge drops in free hard disk space for a while and then the space returns to near old values. A few days ago, when i clicked 'my computer', i saw the properties of the computer instead of 'my computer'. Start menu showed me the same thing. I rebooted my system and things became normal. All my browsers hang for a while. Additionally, sometimes my FB login page looked weird and unlike the regular page (Browser injection???) Then, there are these chinese alphabets in the attached image.
HKEY_CLASSES_ROOT\楖敤䱯乁嘮䍌汐杵湩.1
Is it possible that my system is infected with some stealthy malware? If yes, how do I check if it is really malware?
I am worried to death now. all the paid av, sandboxing, no-scripting finally might have amounted to nothing. :(
Thanks in advance.

