If it's a beeping sound that came out of nowhere, then it has to be hardware. It may be a stick of RAM in your computer, I would open it up if you know what you're doing, and remove a stick and try to turn on your computer and see if it works. If it does, then either that stick of RAM, or that RAM slot has some problem.
If you don't know what you are doing, PLEASE don't open it up and try this, I don't want you to accidentally unplug something and then it won't work at all.
Try to ask a friend if he knows much about computers, or if they have a friend that knows much.
If you really want to do it yourself, you could read a tutorial.
More...
The indicators of faulty memory are legion, but let's start with a few common ones. From the top:
- Blue screens during the install procedure of Windows 2000 or XP. This is one of the surest signs of faulty memory.
- Random crashes or blue screens during the running of 2000 or XP. Note that heat can also be a culprit in the case of general flakiness like this, so you should test for that possibility too.
- Crashes during memory intensive operations. 3D games, benchmarks, compiling, Photoshop, etc.
- Distorted graphics on screen. This can also be related to the video card.
- Failure to boot. This can be accompanied by repeated long beeps, which is the accepted BIOS beep code for a memory problem. In this circumstance, you cannot test the memory with diagnostic software, so your only option is testing by replacement, either at home or at your computer dealer.
Even though it's Windows 2000 and XP, it still applies to Windows Vista.
LASTLY: If it isn't RAM, it maybe other Hardware failure. I REALLY think it's Hardware though, since the computer hangs and beeps. But since I'm not near the computer to check, it could be software as well... If a recovery install doesn't work, then it's hardware.