Beep on Windows startup

Bit of a longshot question here, but I'll try anway...

When Windows first starts up, as the desktop is just coming up, there is a single beep sent to the speakers, with no error message displayed. I recently built this computer, and was wondering if this beep could be attributed to a hardware issue, or if it's more likely on the software end. Anyone had a similar experiance?

Thanks.

is this the only problem, and also can you right click the my computer icon or link in the start menu, select properties, make sure all the ram you actually have is detected by windows. this sounds like what bad ram does, maybe even video card, is your mother board set to give warnings, like halt or beep on errors? i would check out the ram first, then video card. maybe since new built system it is a bios setting that is to blame, may have something not set right, or at all.

The RAM issue is very strange. When I first put this box together I put in a gig and a half of RAM. (3 x 512 sticks) When I first turned on the computer it only detected a gig, and couldn't find the other 512MB. I couldn't understand why a brand new mobo couldn't detect one of three DIMMs. Not wanting to put the 512 to waste, I removed it and put it in another computer. (Where the stick was picked up fine, so it wasn't a faulty stick.)

Any way a bad RAM slot could cause Windows to beep? This is the only hardware issue I could see, as the video card seems to be fine.

this really sounds like ram now, you may have a dram timing jumper on the motherboard it's self, and/or bios settings to set up for the ram to work properly. also did you buy the right ram for your board, did you check the specs on the board and the ram for compatibility? example, someone brought me a home built system with a pc chips(total crap) motherboard, they had 256 megs of pc2100 ddr ram, they bought another exact stick of 256, crucial brand, they put in the second stick ,comp blacked out, wouldnt beep, nothing when turned on. i looked up the specs for the ram and the board, set the dram jumper on the mother board from 100 to 133, set the proper voltages in the bios, which he had many other things set wrong also,and he is happy with his new ram god help him with the pc chips, but if you built this computer, may want to read the manual, if you dont have one, most have them availible for download on thier site.
oh, to get it to the bios screen after the black out i just used the bios jumper to reset it to default, then set it all up from there.most default settings or best performance settings dont always work properly, so setting the bios is important.