Keystrokes lag in every program...laptop slow...Scroll down bar also lags

It all started when my HDD had some issues and windows would not boot due to some missing files. I formatted the HDD and reinstalled windows XP from the original disks. Also installed the applications that come on Dell CD. In addition, I installed Office 2003, firefox and some other apps. At this point, any keystrokes in firefox or Word or even notepad were lagging by a few seconds. Pulling down the vertical scroll bar would also have lag. I noticed that everytime I would open an application or do some heavy processing, instead of the indicator lamp (I believe it's either HDD activity or processor activity indicator) flashing continuously until the application has been opened (or scroll bar pulled down) , it would flash for a few seconds and then everything would freeze for a few seconds, and then again it would start flashing and things would be moving for a few seconds. I.e., processing or HDD activity would be kinda run-freeze-run. At that point I decided to format & reinstall Win XP. The problem still persisted. During the installation process I noticed the weird activity lamp flashing again. Instead of flashing continuously (even when copying files for installation or copying files onto a USB drive), it flashes intermittently. Also, every now and then I get a weird message when booting up that the system could not find a bootable disk (I think it doesn't detect the HDD). I think my HDD might be bad. Can't be spyware since I have already formatted and reinstalled twice. What do you guys think? Is it a bad HDD? or bad RAM?

Dell D620
Processor activity at idle stays low 2-3%

 

There is no processor activity indicator, the cylinder icon is for hard drive activity.

Bad RAM would almost always cause a POST error, so I doubt it's that. Try another hard drive, SATA drives are very common and you should be able to pick one up pretty cheap. I would recommend a 5400RPM Seagate drive, a 500GB one is only $90 on Amazon if I remember correctly.

 

Check the IDE ATA/ATAPI properties in Device Manager to see if the interface has dropped into PIO mode. This can happen if the optical drive has problems reading a disc (or, I assume, the HDD has problems).

If that has happened then the best fix is to remove the affected device in Device Manager and reboot to let Windows redetect it. The interfaces should be running at UDMA-5 (HDD) or UDMA-2 (ODD).

John