slowdown during hdd activity

I've been wrapping my head around this problem for a while(check my other posts). I've been having some problems with a few viruses I got from a friend's hard-drive so I decided to do a clean install of the O/S and switch to the x86 version of windows 7 ultimate. I successfully installed it and the first thing I did after afterwards was to install the trial version of Kaspersky Pure Antivirus. Even before I got the new "collection" of malware my windows kept freezing during random moments (while playing games, copying files, even watching videos), for short periods of time (it was suddenly freezing with the HDD Load LED lightened up and after a while, 20 seconds or so ... it "started unfreezing" with shorter freeze periods. After I saw the same symptoms on the clean install I thought it was a memory or a hdd problem so I ran the windows memory diagnostic and put the HDDs through some scans and tests. The only problem i ran into was a warning message from the smart data the software HD Tune Pro got in the Health status: "Ultra DMA CRC Error Count" was "1". So, at one moment in the past i had a transfer error. It hadn't occurred again.

So, the issue is: I can't even run a full system scan on kaspersky without slowing down my computer to the pace I can barely open a .txt file. During a game installation I have to act like microsoft has switched back to singletasking. :) Ask me for further details, because I think I lost track of things I tried in getting a proper diagnostic for my problem.

It will take a while. The extended tests for the western digital hard drives will take a few hours to complete. I have two HDDs (1TB and 640GB). And yes, I deleted the system partition and reformatted because I was missing that 100MB partition that windows 7 creates for indexing, i think.

You have already told me the major source of your "slowing down", namely, Kaspersky.

Download Microsoft Security Essentials.
100% remove Kaspersky.
Install, run and use Microsoft Security Essentials.

Microsoft Security Essentials is free, automatically updated by MS, non-intrusive, small footprint, the only AV/firewall/anti-malware software which I recommend.

You will find that the majority of those answering questions here are users of Microsoft Security Essentials.
http://www.microsoft.com/security_essentials/

karlsnooks said:

You have already told me the major source of your "slowing down", namely, Kaspersky.

Download Microsoft Security Essentials.
100% remove Kaspersky.
Install, run and use Microsoft Security Essentials.

Microsoft Security Essentials is free, automatically updated by MS, non-intrusive, small footprint, the only AV/firewall/anti-malware software which I recommend.

You will find that the majority of those answering questions here are users of Microsoft Security Essentials.
http://www.microsoft.com/security_essentials/

the problem is that I've had this slowdown for a year or so during multiple installations of windows 7, and this is just a temporary use of Kaspersky because I had the infection problem recently. I experienced this slowdown even after I had a completely clean install of windows 7 while installing drivers and the basic software. I think it may be a hardware problem.
I'm aware of kaspersky being a resource hog, but as I said it's temporary. I'm only using it to clean up my secondary partitions. I think its disinfection methods are some of the best.
Dunno if this is biased but I chose it from this list:
AntiVirus Software Review 2010 - TopTenREVIEWS

at the moment I'm running the fourth pass on the first 1gb ram module, no errors yet. I ran the malwarebytes before and found 12 infected files that were cleaned up (i looked up the malware that i was infected with, and none seemed that critical). I'm wondering if memtest really needs to complete so many passes to get an accurate result :). Also I have no overheating issues, I always monitor the internal temperatures. The only weird thing I noticed it's that the hdd temp seems to stay around 45 degrees celcius (load or idle).

I will uninstall kaspersky as soon as I complete the full scan in safe mode (if I'm gonna be able to complete that task).

I would appreciate any other suggestions to help diagnose the problem, meanwhile.

there were no kind of repairs made to the computer. I experienced this problem as soon as I upgraded my mainboard to this MSI P43 neo and the video card to the MSI Nvidia 250 gts. I also bought a new low budget case. So, there might be a power source problem or a mainboard problem here.