Even XP has grown in its needs. You'll want 1.0GB to 2. As to noise you can clean the machine and hope it's just dust.
I have windows XP sp2 on Dell Dimension 9150 ...tower always seems to be "running" (noisy, laboring) with only a web browser open ...have been running system scans but only findng cookies, no malware, etc. I do get a pop up request now/then for a "smart update" that is suspect. Now I'm getting the windows "clunk tone" off & on that won't stop even after re-booting. Do I have some funky kind of OS corruption or is this classic virus signs? I had XP reinstalled 3 years ago was fine for awhile but last few months things are sluggish. What's my next move?