I am having a problem with the Jazz Jackrabbit game on pure dos. The game starts and I can perfectly play the first two levels. When the second level is complete, the level clear animation appears, and the computer is completely locked (ctrl+alt+sup stops working too), the monitor turns off indicating "no signal." I have tested other ms dos games, and they seems to work well.

My configuration is:

Futro s400 Thin Client (Exactly the same hardware than HP T5720)

AMD NX1500 Processor (K7)
SiS chipset
SiS Mirage IGP
512MB DDR 400 RAM (128MB for graphics)
Yamaha WaveForce 192XG PCI Sound card with pure dos drivers (SiS modded)

Things that I have tested:

Patch with patchcrt and tppatch.
Original executable file with the processor slowed down disabling L1 cache with SETMUL.
With the patched file, modify the processor to 3x multiplier with SETMUL to have a 400MHZ clock (the minimum it can reach).
All sound card options, Sound Blaster 16, Sound Blaster Clone, Sound Blaster PRO, and no sound card(internal speaker).
Clean boot with no config.sys/autoexec.bat.
emm386 and himem activated and deactivated in config.sys.
I have tested three different Jazz Jackrabbit CD versions, and the floppy one.

I have no ideas to continue testing. Jazz Jackrabbit is one of my favourite games and one of the reasons of making this setup. If somebody can help me I will be grateful.