9
O20 - Winlogon Notify: rpcc - C:\WINDOWS\System32\rpcc.dll

The presence of a backdoor means a hacker has control of your computer. If you want to try and clean it, I would recommend installing a good third-party firewall like Zone Alarm and visiting a few online anti-virus scanners. I would recommend Panda, Trend Micro Housecall and F-Secure. (You will have to disable avast! while scanning.)

For some time, my PC kept uploading data even when I don’t do anything and the upload value is thrice the normal (allowed) value. When I removed this entry with hijackthis, my upload rate went to normal. No wonder my internet connection became unstable (dropping every several minutes). I don’t know thatwas the sign of backdoor infection at that time.

I’ve removed the suspicious entries in FreewheelinFrank’s posts with hijackthis, and did a full system scan with Trend Micro online antivirus. I also installed ZoneAlarm, for future protection (although it conflicted with some filesharing applications when I first started it). I also considered to start using user-privileged accounts in the future to prevent ‘them’ getting administrative rights on my computer. My problems are now solved (although it’s pretty heavy on my mid-end PC to have AVG, a-squared, zonealarm, and avast auto-protections enabled at the same time.).

Thank you, FreewheelinFrank, polonus, Tech, DavidR for all your fast & great help, I really appreciate them.
May we meet again in the future.

P.S:

Your system is not up to date. Is there any reason you haven't updated to SP2?

I’m living in one of those ‘third world’ countries where getting a copy of windows SP2 is pretty hard.
So… you know the rest ^^.