Dell Slow Showing Explorer

My dad has a DELL 2400 basic desktop about 2g mhz cpu, XP pro, 256 RAM. It seems extremely slow although, on my login, I've disabled all DELL startup items that seem like memory hogs. I know the RAM is low but I often use a computer with only an 800mhz processor with similar software and have better results. I've been spending a lot of time at his house recently because of various family illnesses and can't quite figure out what is wrong with this computer. Where I see the problem is when minimizing Firefox and then trying to open a folder off the desktop (basically launching explorer.exe) it takes between 30-45 seconds on average to open explorer window. No "flashlight" icon or anything like that just no response because both activity lights are fully lit on the box, indicating full RAM usage. I've defragged, used CCleaner, looked at CPU usage about 5%, paging file is low as well. I know installing XP fresh from a disk will get better results from this computer but it simply isn't my computer. Any ideas of what could be going wrong or why explorer has so much trouble displaying the contents of a folder?

 

Is it set to show thumbnail view?

 

No, I use icons on that computer. It's not about the system drawing thumbnails slowly or analyzing filetypes I'm opening folders with 5 files none requiring thumbnails [the whole system locks up because of high RAM usage just to open a folder] it doesn't make sense, CPU usage is still only 5%, it is like it can't give me a simple directory reading on a folder. There is no plausible reason for such an extended delay, I just can't figure it out. Thanks for suggesting I check this.

 

Umm... Probably barking up the wrong tree here but, what is the mem usage of Firefox and explorer at the time? Also what is the system cash set at? One more thought, if TweakUI is installed, can you check the number of customized folders to remember for explorer?

I don't really hold with these to much but something you might try is a ram optimizer. The one BigBazza has recommended in the past:
http://www.majorgeeks.com/FreeRAM_XP_Pro_d1670.html works well. It helped me out while I was finding a bit of a bug.