I've been noticing some problems with my computer lately. I have a dual-boot Windows XP Pro/Debian Sarge machine, just recently I was having some problems with both operating systems. However, the problems were more pronounced in Debian. It's not one specific problem but a series of them. First I tried installing Azureus under Linux. I've installed it in the past and I had the Java SDK 1.5.06 on the machine set in the path. However, it echoed the version when queued, however when I'd run it it say I need at least Java 1.3 or higher. Then in a few minutes it would work. I would try to open a new session under a terminal and it would shoot out an error and not let me log in then it would work later on. I wasn't able to use any commands for a while I'd get an error and then it work. Azureus would start but then would never get a connection even with hundreds of peers and the port open. Networking would startup on boot but it wouldn't work so I'd need to restart it. It was just random problems. Under Windows I had an issue where windows media player wouldn't work and then it would and other goofy bugs like in Linux. I definetely believe this is a hardware issue but I'm not sure what. I have a 200GB Western Digital hard drive which I've had for a few years and I'm wondering if you think this might be causing it or something else. Any suggestions?

If you get inconsistent errors like this then you are correct in looking at a hardware problem.
Personal experience in the field would point firstly to the power supply. Sounds odd but if your power supply is starting to fail it does not provide the correct voltage on the 5V rail to the processor. The 5V rail should be providing greater than 4.9V at rest but if this value falls below 4.8V under load you will see these kinds of problems. There are ways of measuring this using software system monitors or direct measurement off a 5V line. The next likely cause is memory and I would suggest an extended test using memtest86.
The third problem may be cooling related. Again a monitor can check this. If you haven't opened the box for years then the cooling fins on the heatsink could be clogged up with fluff and dust.

Thanks for your reply. The power supply was replaced within the last 2 months with a quality 400W supply. The old one was causing a lot of issues, including overheating problems, but this one's pretty new. The heatsink was replaced with the power supply since I thought it caused the initial overheating. I can see it overheating however the internal temperature through the BIOS is 38 degrees Celsius. Memory was another thought of mine and I'll look into it later. One problem I forgot to mention was my hard drive not being detected on occassion through my computer. I'd turn it on and I'd get no disks found errors. I'd have to go in play with the cables, and then it would then kick in. This has been going on for awhile. I did order a new hard drive since I am concerned with this one dying anyway. It's 3 years so it's time for a new one. I currently use an IDE drive, can't afford a SCSI yet, but the one I got has an extra 50GB of space and a 16MB cache (my old one was 8). They claim it's also designed for higher reliability. So at least I feel like I'm getting something better than just replacing an old drive.

There are 2 possibles here.
1. The ide cable is damaged leading to interment disconnection or;
2. The pins in the connector block on the drive may be loose or damaged. I used to see this on some of the old drives where they had poor design but most of the manufacturers seem to have solved this one. This is also quite serious because at any given time this connection can fail and you will never get access to the drive again.

try recovering bad sectors, see if that helps.