Yeah, in agreement about registry cleaners. As I said, they do tend to break your windows. I'd also like to clarify what I meant about the registry and performance:
However you look at it, the Windows registry is still a database at heart. The more entries there are, the longer it may take to process/locate stuff. My Windows used to slow down over time too. It is only since I began to clean my registry
manually (which entails deleting things I know I can and leaving what I'm unsure of alone) that my speed has remained decent. Another practice is, as I mentioned earlier, get a sanbox program (I use Sandboxie) and install all the apps that you can in your sandbox. It makes it easier to start fresh. Admittedly, since I changed to x64 I have had a few apps that don't run properly sandboxed but the majority work fine. That's what led me to that conclusion of the Registry but it could well be coincidence.
For anybody willing to test the registry theory (I wouldn't) and put an end to one of the biggest debates in PC history, make a batch file, do the test
*By clicking on the code snippet below you agree to take responsibility for any loss / damage resulting from your use of this code. Neither myself nor anybody associated with TGC and these forums accepts any liability.
rem ***WARNING: VERY DANGEROUS USE THIS CODE AT OWN RISK ****
@ECHO OFF
SET var=1
:start
SET /A var=%var% + 1
REG ADD "HKCR\*\WastEntry%var%"
ECHO Added key "HKCR\*\WastedEntry%var%"
IF %var%==100000 GOTO endp
GOTO start
:endp
ECHO Have fun cleaning it up...
PAUSE
Seriously, the above was a joke. Don't do it... No.... No!
On a serious note, I think though, running processes also contribute to sluggish behavior. But a lot does also boils down to where and when it slows. That usually gives a clue as to if there's a hardware problem and what it is.
Now that I think about it, maybe it could be the physical number of files and folders on the hdd too (slows reading the MFT down?). I wonder how much weight that theory carries. I'd test these out if I still had more than 1 PC.