Hard Drive Light on Continuously

Hello. Not sure if this is a hardware or software problem but here goes. This is an eMachines D4362, P4 3.0 GHz, 1 Ghz RAM, Windows XP Home SP2. A week or so ago I noticed that after the computer runs for an hour or so it starts locking up, and the hard drive light stays on continuously. Also after this occurs, it will not shut down (locks on "Windows is shutting down"). A manual restart corrects the problem, but it reoccurs after a period of time. What I have done so far:
Ran malware removal as per MajorGeeks Malware Forum. Found and removed a few items. All scans now come up clean. A Seagate diagnostics program indicated that the hard drive was bad, so I replaced it with a new one, the problem seems better (computer runs faster and doesn't lock up as much) but eventually the hard drive light stays on continuously, it slows down, and begins to lock up. I opened up the case, blew out some dust, removed the HS and CPU and reinstalled with thermal gel as per Arctic Silver instructions. Added a pci slot fan, ensured that all fans (have 3 now) are running ok. Monitored temperatures with Speedfan. CPU temperature normally runs in the mid 40's, occasionally may reach low to mid 50's.
When the hard drive light is on continuously I have looked at Task Manager. CPU usage is very low (0 to 2%). I have terminated all of the processes that I could, makes no difference. The only thing I can do is manually shut down (Using the power button).
At this point I am at a loss, other than to possibly reformat and reinstall the OS. I guess that would definitely rule out software issues.
Any advice would be most appreciated.
Thanks.

 

Hello. Not sure if this is a hardware or software problem but here goes. This is an eMachines D4362, P4 3.0 GHz, 1 Ghz RAM, Windows XP Home SP2. A week or so ago I noticed that after the computer runs for an hour or so it starts locking up, and the hard drive light stays on continuously. Also after this occurs, it will not shut down (locks on "Windows is shutting down"). A manual restart corrects the problem, but it reoccurs after a period of time. What I have done so far:
Ran malware removal as per MajorGeeks Malware Forum. Found and removed a few items. All scans now come up clean. A Seagate diagnostics program indicated that the hard drive was bad, so I replaced it with a new one, the problem seems better (computer runs faster and doesn't lock up as much) but eventually the hard drive light stays on continuously, it slows down, and begins to lock up. I opened up the case, blew out some dust, removed the HS and CPU and reinstalled with thermal gel as per Arctic Silver instructions. Added a pci slot fan, ensured that all fans (have 3 now) are running ok. Monitored temperatures with Speedfan. CPU temperature normally runs in the mid 40's, occasionally may reach low to mid 50's.
When the hard drive light is on continuously I have looked at Task Manager. CPU usage is very low (0 to 2%). I have terminated all of the processes that I could, makes no difference. The only thing I can do is manually shut down (Using the power button).
At this point I am at a loss, other than to possibly reformat and reinstall the OS. I guess that would definitely rule out software issues.
Any advice would be most appreciated.
Thanks.

 

Threads merged. Please do not cross-post the same issue across multiple forums. It makes it impossible for others to track if they are having the same issue, or for those trying to help you to follow what advice has already been given. If you problem is found not to be a hardware issue, THEN post a thread in the software forum, and link it to your original thread in hardware so that others can see you have exhausted all those options already. Thanks