800 / 900 still crashing

Hi everyone,Further to my post of last week I had hoped that setting the swap file to system control would cure the crash-to-desktop issue. Unfortunately it did not.Meanwhile I did the following: uninstalled the 737 NG, uninstalled the simulator including manual removal of all remaining files also under Documents and Settings etc. Then I defragged the volume and started the whole process anew. After this I got also the "engine fail" message, but already when loading up the 800/900. When ignoring this message one engine would then fail when approaching V1 during take off. This situation led to re-installing the NG for the third time and now I noticed that the "engine fail" issue did apparently not happen when the aircraft was loaded with running engines. By this time this blasted Sasser virus came into the game and I ran a full update of the available Windows XP patches (15 patches for an operating system on a PC which is just 4 months old, but this is another issue...).Today I tried again to run the NG, first the 800 which failed after about ten minutes, then I tried the 700 which failed also after about the same time. Both scenarios were identical (flight from EHAM to EGLL) and ended probably in the English Channel. The only difference to the crashes of last week is that I now do get the Windows error message. The message refers to the usual files fs9.cfg, scenery.cfg and some diagdx file. But these files are always stated when FS9 crashes. Btw, I had those crashes also with absolutely no other add on installed, neither aircraft nor scenery.One thing came to mind while I was trying the above steps: when the update from ver. 1.2 to 1.3 for the 600/700 came out I installed it but the plane would also crash then. Therefore I went back to ver. 1.2 which funtioned flawlessly during the past months. My question to the PMDG team now is if there might be a problem with Windows (compatibility) or with the upgrade from ver. 1.2 to 1.3 or with both?Any help or patch or liquid measures to lighten my mood will be highly appreciated. Best regardsUweSystem specs:AMD Athlon 3.0, 1GB RAM, Hercules 3D Prophet 9600 (ATI Chipset) w. 256 MB RAM, 170 GB HD, Windows XP Home, German version and the latest set of 15 patches...