Help Please-1st built PC

I just put together a system today and I want to find out a few things.

Ok i got a 2100xp,TT Volcano 6++,gigabyte GA-7VRX Mobo,320wattPS,256crucial 2100ddr,Maxtor 40gig 7200rpm ata133 HD,32mb sis 305.

Ok ive been running into some problems. Motherboard is set on default bus speed of 100, has a switch on mobo to set to default 100/133 speed. I can also adjust it in bios much past 133 although im not an overclocker(dont want to be) im not really sure what the bus speed even does when you crank it up.

So what should this be set at 100 or 133? When it is set on 100 i get a read out of 1500+xp and everything runs fine with about 40/50*c.
When i run it at 133 i get the actually speed read out of 2100xp it runs about 50/60*c. When its running at 133 it seems to get lockups and errors when installing things etc.

What should i do, could it be caused by the heat? or am i not supposed to be running it at 133?

My house is pretty hot where the PC is so its kinda hard to keep it super cool, could that be a problem?

I was also wondering about running HD in ata 133. Does windows XP automaticly set it for the best speed or is this done manually?

Thats basicly all i really was wondering. Thanks for the help in advanced

It should be set on 133. Did you use a good quality thermal compound between the CPU and heat sink ? I'm not familiar with that mother board but if it has an ATA133 IDE controller, then it should automatically run the drive at ATA133. Upon furthur research, the board does support ATA133.

I know with a couple of those motherboard the 7VRXP and 7VRX they came from factory with very aggressive memory timings. check to see what they are set at, that could be giving you lockups at the 133 bus frequencies. also check that when you go to 133 that your memory speed is set at 133 not 166.

it should be set at 133. did you check to see if you need to update the bios to handle the new line of AMD CPUs?