I apologize if I'm posting in the wrong section, but I recently read something that categorized at least one of the symptoms my system is experiencing as 'almost always hardware related.'  Here's a timeline of sorts...

I came back from vacation, hadn't even turned on my computer in two weeks, hadn't installed any new software/hardware.

-Heard a new "BEEP" upon startup, right before the Windows logo appears
-Noticed that the POST isn't showing up anymore when I first turned it on (when the single beep noise is made)
-Have no sound, and get error messages saying that my soundcard is already in use, even though nothing else is running
-I run spybot, easy registry cleaner, ad-aware, even though my system was running fine last time I used it, but I really don't know much about anything and thought I'd give it a shot.
-System freezes a couple of times
-When I restart it, it won't turn off completely even though I leave it alone for an hour.  Hard drive light stays on even though fan is off.
-I manually turn it off, and when I try to turn it back on, the light turns on yellow (not green like normal) and fan starts, but no booting happens, just sits there.
-The next day it boots up, but STILL has the no sound problem.
-I start getting messages saying that my USB port has a power surge, even though I have no components hooked up to USB ports.
-I buy a new power supply, everything stays the same (no sound/USB error messages).  I replace it since it's an Emachines T4510 and I hear that they use cheap power supplies that can cause motherboard DAMAGE after a couple years.
-I try resetting my BIOS because of something I read (took out the BATTERY).  Didn't change anything other than changing my clock and setting the date to 1601.
-Multiple programs are having to close/experience errors (MediaPlayer/IExplorer).
-I hear that the BEEP is most likely a hardware issue, and make this desperate post, even though it might not even be hardware related.
If you have any idea what it might be, or what else I can try, I'm all ears.  Please help if you think you can point me in the right direction because it seems to be getting worse, and I don't want to screw everything up tinkering where I shouldn't.  Thanks!Im stumped but Ill give your post a free "bump" to get it back uptop.

I'll try my best though
 These points make me think the motherboard may have been damaged by the previous power supply and is working at a crippled capacity.

-Freezes at shutdown and needs to be manually shut off
-Freezes in general
-Start up is a crapshoot sometimes it works other times nothing.
-USB ports malfuctioning, Intergrated soundcard not working
-Limited funtionality of windows


Personally I have been in two situations where the power supply and motherboard had to be replaced, once on my own computer(e-machine T2642, just stopped booting completely) and once on my mother in laws computer (COMPAQ somthing, stopped booting intermitently or would boot to blackscreen occasionally would fully boot but limited function)
In both cases the power supply was replaced but computers continued to display bizzare behavior like you are describing. This was finally remedied by replacing the motherboard as well and reinstalling the operating system. A reinstall of the operating system was tried first on the Compaq as well as a replacement power supply but the problems persisted)

I spent nearly 300 dollars to have a computer shop fix my personal computer IE-install a new motherboard worth 75 dollars, the rest was labour, I installed the power supply myself, after that I quickly learned how to install motherboards myself.
The Compaq computer drove me nearly insane untill I found that throwing money at it made it happy.
I spent 45 on the power supply, 99 on the motherboard and 75 on the new case. Compaq computer cases have PROPRIETARY motherbaord connectors that wont work with standard aftermarket motherboards (oh the frustration). Luckly all the other hardware was OK and could be removed and reinstalled on the new motherboard, I did all the work myself this time.

I had another situation where my computer quit booting altogether, it would just goto a black screen, through troubleshooting I found that my video card had died and the computer would not work with it installed (card was replaced under warranty)