You're 512 MB of RAM will run the machine but if you've got lots of programs running in the background, it will cause the computer to hesitate. Heck, McAfee retail and all it's subprograms can cause a delay in opening/closing such programs.. You might try disabling it to see if the issue fixes itself.
Some steps below might help:
Hope this helps.
Windows XP Professional version 2002 Service Pack 2
Dell Latitude 610
Intel Pentium M 1.86Ghz,504 MB RAM
After clicking any desktop icons, I get a delayed response of about 60-85 secs. When I close windows it also takes a while to do or it it will start from the top of the window and it will disappear horizontally...(hope that makes sense)
I ran Windows Defender and it didn't pick up anything and then I removed it b/c it wouldn't update the virus definitions
I ran Mcaffee and it didn't pick up anything
I downloaded AVG 7.5 and it removed a few cookies but nothing inparticular.
I do notice I get get a buzznet.com website that pops up from time to time. I have ran the clean up, defragmenting also but none has done anything. My C: drive has 28.7 GB free space out of 37.1GB Don't know what else to do.