X crash with kernel 2.4.12/.13(-ac5)

[MASSON FRANCOIS ALAIN]

Hello,

--Here is some info about my computer:

Manufacturer: Packard-Bell
Processor: Intel Pentium MMX @ 233MHz
Video Card: Onboard S3 trio 64 v2
XFree: Mandrake XFree68 3.3.6 S3
Distrib: Mandrake 8.0
Kernel: Linus 2.4.12; Linus 2.4.13; Alan 2.4.13-ac5

--Here is the problem:

All run well till I start X.
But then the screen become black, no consol switching.
The SysKey respond.
A telnet or X from another networked computer work.
The system is still running, but the video card seem to be in a unstable
state.

-- Latest known working kernel:
Linus 2.4.9; Alan 2.4.9-ac4

-- About my kernel config:
Sorry but I don't have it on hand, but here is what I remember:

Processeur: Intel Pentium MMX
Video config: no frame buffer, no vga mode selction, no AGP, no DRI.

Please help,
francois

PS: As it's my first bug report, it may be not very exausted, don't tell me
what I done wrong and request futher informotion you need.