Problem: Computer locks up when attempting to open a file or an application and only option is reboot. CTRL-ALT-DEL will bring up dialog saying, "Resources are dangerously low, do you want to close XYZ application?" Answer "Yes", and it comes back with another app until all are closed but still requires reboot. Lockup can occur with only one app running. Appears that some apps are not releasing memory when closing or a bad leakage is occuring.
System worked fine with these apps and configuration for two years. I don't see any installation that may have caused this problem.
Machine: Pentium 120
OS: Windows 95 4.0 Build 950
CPU : Intel Pentium
Physical memory: 48 MB RAM
Page file space: 164 MB free, 20 MB in use
(184 MB total)
Display Monitor : ViewStar 15"
Description : Plug and Play Monitor (VESA DDC)
Max Resolution : 1600,1200
Sound Card name : Creative Labs Sound Blaster 16 Plug and Play
Wave Out Device: SB16 Wave Out 
PnP or PCI ID : ISAPNP\CTL0024_DEV0000\1003006A
Driver : sb16snd.drv
Version : 4.37.00.0155 "4.37.00.0155" Final Retail
Date and Size : 07/14/97 16:00:00 75392 bytes Certified
Current files : sb16snd.drv, sb16.vxd
Hard Drives : C: D: E: Try to maintain minimum free space of 150MB on each
Main Programs Used : AOL 5.0, MS Office 95, StarOffice 5.1, Personal Ancestoral File 5.0. Have resorted to having only one app open at a time but still get lockups.