What are all of the unobvious reasons that my PC would becomes really slow? (Not viruses, spyware, adware, malware, slow hardware, startup programs in the registry, startup programs in the startup folder, startup programs in the win.ini or system.ini files, etc.) I have 3.4ghz and 1gb of ram but my PC is really slow. I only have my antivirus and firewall set to startup at Windows startup. I was thinking maybe all the programs that I've installed are slowing down my PC, maybe loaded drivers, dll, ocxs, etc, slightly incompatible drivers loaded.

1.Spyware and viruses 2.Processor overheating 3.Bad RAM 4.Failing hard disk 5.BIOS settings(update with latest bios version) 6.Disk type/controller compatibility(. New Serial ATA (SATA) disks are faster than old Parallel ATA type.) 7.Windows services(disabled unwanted sevices in services(start-run-service.msc) 8.Runaway processes – Runaway processes take up all of the processors' cycles. The usual suspects are badly written device drivers, and legacy software installed on a newer operating system. You can identify a runaway process by looking at the process list in the Windows Task Manager. Any process that takes almost 100 percent of the processing time is likely a runaway process. 9.Background applications-in msconfig disable all start up items. HKEY_ LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run and HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnce remove the start up items from here also 10.File system issues – Some file systems work better than others for large disk partitions. If the machine runs Windows NT 4.0, Windows 2000, or Windows XP, you should use the NTFS file system for best performance. Network Support Enginner

If you have checked everything that you posted, then it may be a bad component somewhere. Since when something goes bad, it will generate a great deal of heat, try using a heat detector like Speed Fan Tomorrow the Stars!

Speed Fan Tomorrow the Stars!

I recently saw a slow system that was caused by a failed/failing optic drive (CD Burner). Disconnected the bad drive and problem solved. There are lots of things that can contribute to system slowdown. Good luck sorting out yours. I used to have a signature but it disappeared and I just couldn't be bothered writing another so please feel free to ingore this.

Check the temp files on the HDD. I cleaned a machine yesterday that had a whooping 687Megs of temp files! There's often a lotta junk in the trunk ;-) "When Life gives you Lemons, eat 'em raw"

I find virus checkers slow me down by checking everthing that is done on the computer.