This can be a worthwhile system if you don't plan to add too much to it. The biggest problem you have is that there isn't any onboard sound and you're missing the expansion card riser board to allow you to add one.

I actually have a Vectra that I use as a server, but it's a P3-500. Pretty reliable.

If you are having trouble finding an AT power supply, you can buy a brand new Athena Tech 300watt from Newegg for around $20 and I am not sure about the VRM but I would assume it would be for Pentium mmx cpu's with split rail voltage. The older pentiums ran off of a single voltage and latter ones required two different voltages. Hope I could help a bit! they are interesting boards, hold on to them for sure. After a quick ebay search I found this: http://www.ebay.com/itm/D3659B-HP-MEMORY-RAM- … =item2c75a5d135

Also the k6-2 is unlikely to work as it is a SS7 cpu, the 233mhz mmx should work with the VRM, might without it. for now I would say stick your 100mhz classic in there to be safe. Finding the backboard is the major problem with this setup, along with the proprietary case.

Such an old thread. If anyone happens to stumble over such a Vectra mobo, it doesn't work without a VRM. It's needed to convert 5V to 3.5V and lower for Vcc and Vdd. Although it could run with a few jumpers instead of a VRM if the PSU had a P10 aux connector with +3.3V like HP did.

That's not the greatest 430HX board you can find, but quite decent anyway,

Digging again this message for completeness in case someone need any information about this card.
It was used in the revised Vectra VL/5 and XA/5 Series 5 very similar with the previous Vectra VL/5 and XA/5 Series 4 line of products. The motherboard was used in the desktop and minitower versions. The difference being the daugtherboard with ISA and PCI ports being different with less ports on the desktop version.
The Series 4 had a i430FX chipset and the Series 5 replace it with a i430HX adding among other things, the ability to manage an additional PCI port, embedded USB 1.0 and Pentium MMX support up to 233 MHz (compared to 200 MHz previously). Another upgrade for the equipped motherboards only is the embedded video chipset is upgraded from a S3 Trio64 to a S3 Trio64V2 still expandable from 1 MB to 2 MB of VRAM. The PSU connects the 3.3V live near the CPU and for Pentium processors, only a passthrough is needed but for Pentium MMX, a 2.8V VRM is required so with no passthrough or VRM the card will not work. Pentium MMX 266 MHz are not supported officially as the board cannot set that frequency and there were no 1.9V VRM produced by HP. That said, the VRM port is compatible with the Intel specs. In both Series 4 and 5 only 64 MB of RAM is cacheable, that is done with with L2 160-pin 512 KB of synchronous cache module. To my knowledge, as I have only both, 256 KB and 512 KB modules, I think only those size where officially produced and are used since the Vectra i80486.
The power connector is not AT compatible, but HP proprietary. Additionally, on some variants a 3.3V power connector can also be plugged in the ports expansion daughterboard (riser) to feed the cards.
What is nice with the HP motherboards of this era is that the card is inserted by sliding it through plastic rails and is then locked into position with a lever.
What is less nice, is that apart from the standardized I/O connectors, every other connector is proprietary from the PSU to the front panel passing by the fans.
So without the rest of the computer it is quite useless. Finally this Vectra/Kayak computers parts were build to last as they are almost indestructible using very high quality electronic components and are quite hard to find this days.