You are running two anti-virus programs...Bit Defender and AVG Anti-Virus 7.0....This is an absolute NO-NO. You should never ever run two anti-virus programs at the same time on the same machine. This can actually lessen your protection rather than increase it because they will battle each other rather than do the job they are designed to do. You must totally uninstall one of them...your choice but one MUST go.
You are also running at least a portion of Norton/symantec anti-virus also...this shows in this entry;
O23 - Service: SymWMI Service (SymWSC) - Symantec Corporation - C:\Program Files\Common Files\Symantec Shared\Security Center\SymWSC.exe
Evidently at some time you also used and removed Norton Security Center. Look first in Add/Remove for Norton/Symantec. Uninstall anything found.
Next do a file search on the computer for anything Norton. Remove all found. Then do another search for anything Symantec and remove all found.
You have got to remove all but one anti-virus program.
You also mention using Spyeraser...don't. I don't see it here in the log but it does NOT get very good reviews, UNINSTALL it. Stick with the others you mention.
You said you use Sygate Firewall...where is it? Your HJT log does not show any firewall running.
You also state that you NEVER use Internet Explorer, if this is the case then why are you using Ashampoo PopUp Blocker for Internet Explorer? This is totally unnecessary. Firefox has a pop-up blocker, there is no need for an outside one. Uninstall this also.
Your O21 - SSODL: WPDShServiceObj - {AAA288BA-9A4C-45B0-95D7-94D524869DB5} - C:\WINDOWS\system32\WPDShServiceObj.dll
is a perfectly legitimate file. Don't worry about it. It's found on many computers. It is not a problem. Windows Media Player 11 is also fine.
Your main problem is TOO many security programs running at the same time this is why the computer is slow. I see nothing in your log, except the extra anti-virus programs which would definitely cause you a problem.