Maybe I'll boot, maybe I won't

My girlfriend’s computer will not boot consistantly. I’d say once out of every six times it will not boot up. It doesn’t even perform POST (at least the BIOS doesn’t load), but the power light does come on and so does the drive light. (The drive light stays on, it’s not reading data).

Since she bought the machine (foolishly) from a large computer maufacturer, she took it in to them to have it serviced. They said it was a problem with the Ultra-ATA card (which seemed odd to me - I work as a help desk technician). I maintained it was a faulty power supply, but since the large corporation was footing the bill to repair it, she just took it in.

Well after three weeks (!) we got it back yesterday and guess what? It still has the same problem! What I want to know is am I correct in assuming that the power supply is bad, or is there some other possible causes? The machine is less than a year old and has no other problems other than the boot fault. Please feel free to get as technical as you need to. Thanks.

Loose cards/memory can sometimes do this. If they aren’t completely seated in their slots, it can cause wacky symptoms and is almost impossible to detect by just looking.

Unfortunately I have no one to blame but myself since I built the thing. The problem is that I have to cycle the power twice almost every time in order to get it to post, but there doesn’t appear to be any problems with the machine otherwise. I’ve reseated all the cards and DIMMs several times with no change. I figured it must be some timing quirk with my VIA MVP3-based motherboard.

I’ll be interested if anyone has any thoughts on this as well.

Possibly the power supply but not necessarily. Sporadic boot failures are most often caused by loose cards or components, a motherboard or memory DIMM incipient defect, a failing keyboard or a resource conflict.

Things to do.

1: Remove and reseat components (you’ve done this). Swap components around and put in different PCI and ISA slots than they were originally seated in.

2: Swap current DIMM with substitute for a week or so and see if problem persists. If memory consists of multiple DIMMS try to run system with one DIMM for a while.

3: Check BIOS setup and reset BIOS to baseline speed defaults.

4: Try a different keyboard.

I recently got a new motherboard and had a booting problem. I tried everything I could to get it to boot ok but nothing seemed to work. Someone suggested I reseat the processor but I foolishly didn’t. Reseating the processor cured my problem and now my computer is fine.

My money is on the power supply. AMD chips especially require 300W power supplies to ensure full stability, while Intels (and their motherboards) can be downright ornery just from the interference from a power supply. AMD has a recommended list, which you can start to look for at . The Sanford Box just has the power supply hanging outside, away from anything it might wish to screw up.

Oh, yeah! As Astro alluded, keep the top and bottom PCI slots empty if possible; the top one shares an IRQ with the AGP port while the bottom one often conflicts with the topmost ISA.