Problems booting

[Odysseus]

I recently replaced my old power supply (a generic 350W that came with the case), with a Thermaltake 480W and since have been having problems with booting. I installed the new power supply and the computer booted and ran fine for the first day. The following day I encountered my first problem, while booting I got a message "Reboot and select proper boot device.....etc."
I restarted the computer just thinking it might have been a glitch, it started and ran fine. Unfortunately, that wasn't the end of the madness the problem progressed. That evening I rebooted before playing a game and encountered the same problem, but this time I noticed that it was not detecting my primary slave boot device (CD-ROM/DVD drive). I checked my BIOS and tower to ensure that all of my hardware and cables were seated properly and found nothing out of place. After some time I got it to boot properly again by just restarting it. Being curious I shut it down right away and tried booting, it didn't boot. After all of this I decided that it might have been my new PS so I replaced it with the old and encountered the same problem. At the advice of a friend I tried to test my RAM using memtest86, but doing this I may have encountered an additional problem. I have only tried to use the floppy drive (my 3rd boot device) once since I built the computer (two months ago) and it didn't work. I assumed at the time that it was the old floppy that might have been damaged. I made a floppy for the memory test and ran the program, it didn't run like it should have. ( http://forum.pcmech.com/showthread.php?t=118693 ),
I made a second floppy and that didn't work either. After all of this I am thoroughly frustrated and confused, it boots occasionaly but takes far longer than it ever had before. I wonder if the problem could somehow lie within the floppy drive, or why at times it does not detect my CD-Rom drive. They are not connected to the same IDE cable so I don't think the problem relates to that. Any help would be much appreciated.

[HAL9000]

Disconnect your floppy drive... does it boot properly?

[Odysseus]

Thanks for the help but, that did not work. I still get the same problem, although it has booted up recently it took about 2 min with a long pause at a black screen with only a flashing curser.

[Moose on the Loose]

Well since your system was working fine before you replaces the PSU, maybe you just had some bad luck and had a faulty PSU ? Sorry if I'm stating the obvious

[Odysseus]

Thanks but, I tried both the old and the new psu. I encounter the problem with them both.

[Ich]

Try to clear CMOS by jumper.
Maybe, you've forgot to plug the 4-pin connector to your MoBo?

[Odysseus]

I took Ich's advice and cleared the CMOS but that didn't help either. After I reconfigured the BIOS the problem still remained. I am now beginning to believe that my motherboard (Asrock K7V88) may be the source of the problem since more issues have risen and none of the prior mentioned have been resolved. The most recent problems were my USB ports temporarily not working followed by the "blue screen of death" after I shifted my tower to look at the back panel, and then a message upon posting that there was an error detecting my hard disk. Since then I haven't been able to get it to boot at all. I looked for shorts in wires but was unable to find any, later on today I plan on completely tearing it apart and examining each individual wire and piece of hardware. I was told that this was a decent MOBO, if anyone knows of another good socket A MOBO for an AMD Athlon 3200+ with the potential for overlclocking please let me know. Thanks.

[Cricket]

Asrock is the economy line for ASUS. If you're sure the motherboard needs to be replaced, the ASUS A7N8X would be a good choice. The ABIT NF7-S2 would be another good choice.

Cricket

[Odysseus]

Well, I took everything apart and looked for something out of place or a short in a wire. I found a molex connector with a loose pin that looked as if it had grounded at some point in time but, where I don't know. I read a posting where someone had a multitude of problems because of not enough thermal paste or it was old or something. I've never heard of this before but if it is possible that could be the source of the problem. Not to long ago I removed a thermal sensor that was located under my processor, hence I had to remove the heatsink. I left the original thermal paste because of a lack of new grease and a local computer shop (sucks!). The PC had worked after this so I didn't really consider it. Thanks for the recommended Motherboards Cricket, I will look into the new ones as an option. Is there a test that can be done to check the motherboard?

[Cricket]

Reusing old thermal compound isn't recommended, but all that would happen is the processor might run a little hotter than it would if you used fresh compound. And you don't want to put too much thermal compound, that would prevent the metal surfaces from making contact and thermal transfer wouldn't occur (too much thermal compound acts like an insulator). You only need a very small amount of thermal compound between the CPU and heatsink.

The only way I know to check a suspect motherboard is to use it with a known to be working CPU, video card, monitor, RAM and power supply and see if it POSTs.

Cricket

[Ich]

What does "the blue screen of death" say? Copy those letters&digits and go on the microsoft.com and search for it in the troubleshoting.
It also can be a bad sample of MoBo.

[Odysseus]

Well, After all else has failed I have ordered a new MOBO, it should be here today so I'll cross my fingers and give it a try. If this doesn't work I think I have got myself a very expensive doorstop. Thanks to everyone for all of the help.