Hardware gurus, I need your help. For background on my problem, please read this thread first. First, I can't get my mb to clock right; it defaults to 100 mb bus, but I can't change it to 133 fsb in bios...it simply shuts down after making the change in bios and 'save and exit'ing. OK, so my Athlon Xp 2100 runs as a 1500; I figure after all the troubles I've had I'll live with it for a while. However now I'm suffering from random power-offs...well, not really random, either; my system will power down when I try to run certain executable files (like driver updates), or when I try to multitask (for example, I wouldn't dare open Photoshop while writing this, it would crash). I haven't been able to isolate the problem with the crashes, either. I've tried every conceivable hardware combination: 2 different (new!) motherboards, two different psu's (neither new, I still wonder), an AGP and a PCI video card (both new!), 5 different pc2100 rdram chips, (3 new!) and a brand new Athlon XP 2100+. Now I'm suspecting the hard drives, my two Maxtor 40 gigs; but even with no drives installed I can't set the fsb to 133. WHY? (One of my motherboards has a jumper to set to 133, but then I can't power up). I've been struggling with this problem for weeks and am at the end of my rope. I'm thinking of buying a new barebones system just to gain some peace of mind. But I've got all this brand spanking new hardware that I can't use!!! I've been searching the web for help but have come up dry. Please, someone help me diagnose this problem! My old Soyo Dragon Plus mb used to run fine with automatic settings (until I fried it, that is). What should I try next? I'm almost out of hope, but I'm giving you guys one last shot. Thanks in advance for all your efforts.