Closing the question because I found this answer on K7S4A bulletin board
http://pub65.ezboard.com/fk7s5amotherboardforumfrm10
- thanks for your help
K7S5A and 2000xp same problems
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I had the same 2000xp and the same problems. I run W98SE. The pc would run ok at 100/100 but at 133/133 it crashds and froze and was unusable. I also got occasional cold boot ?checksum bad? with lost cmos. I read loads of postsand did the following things, in order of listing. None of them made one bit of difference
1. Chipset heat sink removed and replaced with conductive paste and super glue.
2. I had 2 strips of 256sdram. I tried one only, swapping which I used, and I swapped their positions.
3. I installed a single strip of 256 Dram, and it is still there.
3. I swapped the ATI Radeon VE 7000 for an Nvidia Riva TNT model 64 with 32mb.
4. I used a better cooler and got the cpu temp down from about 58C to about50C.
5. My psu was rated at 350 watts but only 15 amps on the 3.3v line. I put in a 420watt rated at 28amps on the 3.3 volt line, 35 amps peak.
6. I removed the modem and left it out.
7. Took the side of the pc case off and left it off, reducing case temperature.
NONE OF THESE THINGS MADE ANY DIFFERENCE TO THE PROBLEMS.
Then I read a post by DaVinci. He said that the drivers supplied on the cdrom with the board are crap and to download the latest drivers, but only to install the AGP port driver, going via device manager and update driver, NOT using the setup route. He also said to download and install the latest drivers for my Nvidia Riva TNT card. I did both of these things, following his instructions. The pc now runs at 133/133 withabsolutely no freezes or crashes and I am totally happy with it,. . .