FS 2002 freeze up

[Dougx]

For about the last week FS locks up, not the " sorry MSFS must close " window. The lock is totally random with respect to acft, time and function. It usually happens when
I click to lower gear, change views or sometimes just flying straight and level. There is nothing I can do but hit reset and go through the full comp restart routine. This freezing can happen in the first 5 min. or after an hour. No new hardware, all running prog's stopped , frequent defrag, ran dxdiag, no problems. I am stumped!!!
P-4 @ 2.4
MX420 64meg  agp 4x, older driver 3.xxxx
98SE
40 gig hd 75 % open
DIRX 9.0
512 ddr
FS2002 pro
CH prod force fx stick
400 w p/s
2 fans (case)
contrary wife
grateful for any directions....... Doug