Hello! I recently noticed that my hard drive activity light has been staying on all the time,not as bright as when actually using a program but STILL it's on.Is this normal? Welcome myhigh, To answer your question we are going to have to know more about the hard drive. Such as what hard drive are you using (what model)
Unless your computer is running slower than USUAL or you can't access certain things on your computer, I wouldn't worry about it now.What OS is this?
How LONG has this been happening?
Did you make any changes prior to it?
What protection do you have?
Does the computer make any noise when this is happening?

We don't have much to work with at the moment.  One possibility I can offer is that maybe your computer is auto-defragging, which SOMETIMES happens when a computer is left idle for awhile.  Does this happen at any specific time, or is it constant?The operating system is XP home edition media.I'm not sure how long this has been going on as this is a newly loaded system.I have AVG virus protection on it.NO. the computer is not making any noises when this is happening.The hard drive is a SATA western digital caviar 160 GB .The motherboard model is ASROCK DUAL VSTA.I recently added alcohol 120% and it did say something about KERNEL debuggers as i was installing it...When was the last time you updated AVG and performed a scan?

Unfortunately, I'm not too familiar with Alcohol, so I'm not sure what kinds of changes it makes to your computer.  You could try uninstalling it to see if that makes a difference (you can always reinstall it), but I don't know if that'll change anything.

Check your Task Manager (Ctrl + Alt + Del) and click on the Processes tab.  Is there anything with an abnormally high Mem Usage?  Do you have dfrgntfs.exe running by any chance?