hard disk runs intermitently

Is your anti virus software up to date? Make sure that it is and scan your system for viruses.

Next, Press CTRL+ALT+DEL -once- to bring up the task manager when the HDD is spinning to see if you can identify what might be doing this. What OS areyou running? Please post a comment w\ that info.

End task on items that don't belong in the task manager. If you're not sure, post a comment w\ the list of what's running.

Do some system clean up in Safe Mode (press F5 or F8 at boot to enter Safe Mode). Go to Start, Programs, Accessories, System Tools and run: 1-Disk Clean Up, 2-Scan Disk, standard not thorough and allow windows to fix any errors, and 3-Defragment. This is for Windows 98, you'll need different steps for NT or 2K.

Reboot to normal mode. If problem still exists, you will need to check MSCONFIG to see if there is something that's running at startup that doesn't need to be. Check this site for help with MSCONFIG:

http://www.modempool.com/loosecruise/msconfighelp.html

(remove spaces from the URL)
HTH

Windows ALWAYS accesses the hard drive on a sporadic basis when the PC is on.

One of the tasks is to verify that the links to recent documents are still valid.

Unless the activity is for a long period of time, and your anti-virus software is up to date, there is nothing to worry about.

Chas

Totally agree with Answer3.
If you are using Anti-Virus Software it continually monitors and reads/writes the disk at certain intervals anyway this is why you need to disable AV Software during a Defrag.
One further point though, the memory problem you refer to as not enough system memory should be addressed by ensuring that your memory is set to 1 and a half times system memory.
This can be changed by goping into control panel system and right clicking and then change virtual memory to 1 and a half times the PC's RAM.