I would appreciate any help with issues and doubts below reported.
I have a K6-2 450 working on a FIC VA503+ (1.2), 160 Mb RAM (128 on DIMM1 and 32 on DIMM2 - both PC100), and Win Pro 2000 SP4. The computer was working perfectly until two weeks ago when I decided to make some changes. The first one was the installation of Norton Internet Security 2006. After that I removed the 32 mb SDRAM stick from DIMM2 and replaced it by a 256 MB double sided PC100 SDRAM stick and lastly I installed a 3Com Etherlink XL TPO NIC on PCI3. On PCI2 I have a Motorola SM56 Fax/Modem. PCI1 is empty. My video adapter is a SIS 6326 8MB AGP and my sound board is a ESS 1869F audiodrive on ISA3. My bios version is 1.15JE37. My problems are: System boots up mainly when I am on line (dial up); Instead of 384 Mb of RAM, memory test just recognizes 256Mb. Regarding the memory, I really do not know what to do, but I have noticed that IRQ11 is sharing the PCI to USB controller, the SM56 and the 3Com. I do not have anything conected full time on the USB or the 3Com. For the boot up, I have checked the system bunch of times for viruses, malware and found nothing.
Anyway, your memory problem could be due to the use of incompatible RAM. This happens quite frequently. It's cheaper to produce high-density modules, in fact, the higher the density the fewer the chips, the cheaper to produce.
Otherwise it could be a dirty DIMM slot. Try reinserting the module a few times.
Thanks Crashman, actually the first 256 mb stick did not work, than I went back to the seller and replaced it by another one, from the same manufacturer - Samsung. I have already changed the slots but I just get 128 mb from it, but I will try again. Any tip about the best sdram for this mobo? Rgds, Marcelo Hipolito.