You don't have enough free RAM - you should have a minimum of 32 megabytes for Windows 95 and Windows 98, 64 MB for Windows Me, and 128 MB for Windows 2000 and Windows XP.
Your hard disk is too slow - try optimizing it using Defrag. If you have some money burning a hole in your pocket, you might want to invest in a new, fast, huge hard disk.
You don't have enough free disk space for a swapfile - you should have a minimum of 3 megabytes of free disk space for each megabyte of system RAM.
You have 850 fonts installed. If you can survive without all those fonts, try removing 600-700 of them to see if that makes a difference.
Your network drivers (LAN, Dial-up Networking) take too long to load - try disabling them to see if it makes a difference.
Too many programs are being loaded at startup - check your Startup folder and eliminate any unneeded shortcuts.