I recently upgraded to WinXP Home from Win98, and I'm experiencing some intermittent slowdowns, for example if I have 2 or 3 explorer/IE etc windows open and try to switch between them, my PC will grind to a halt for anything up to about 10 seconds or one of the programs/windows will "stop responding". I have 256mb RAM, AthlonXP 1800+, 40gb HDD and background programs are - AVG, MSN, ZoneAlarm.
I also notice sometimes one the windows are switching the freeze and the contents are completly white for a few seconds, also the tack bar sometimes becomes white in places where windows overlap it or dialogue boxes appear.
I dont think so, the background programs take minimal memory and even with say 3 IE windows open I'm only using 60% of the RAM. My HDD is defragged regularly and is no more cluttered than it was with Win98 (which I had no slowdowns with).