<<...my machine's sound started to become distorted and scratchy at random times. The Windows startup sound is almost always distorted and many times when I am playing a game the sound becomes scracthy or seems to skip. The machine has never before done this and I dont recall doing anything new to the machine last weekend. The wierdest part is that the sound distortions come and go at random intervals.>>
That could be due to damaged sound drivers. I would just remove current installed drivers for audio...and then reinstall same or update.
Could also just be failing hardware.
<<...the machine seems to only want to start up in XP if the External Harddrive is turned off (if it is turned on it gets stuck on the screen with the Windows Flag and the green loading bar on startup...>>
Known issue, I believe...similar to issue with flash drives installed at boot.
I believe problem arises from fact that XP senses hardware for which drivers are not yet loaded...and this becomes confusing. Simple solution is to not turn on external drive until system boots fully, since it cannot do anything useful until then.
<<...my machine also seems to get stuck whenever I try to shut down or restart.>>
Troubleshooting Windows XP Network Problems - http://labmice.techtarget.com/windowsxp/Tr.../networking.htm
Troubleshooting Windows XP Shutdown Issues - http://www.theeldergeek.com/shutdown_issues_in_xp.htm
Windows XP Shutdown Troubleshooter - http://aumha.org/win5/a/shtdwnxp.php
<<...an error box appear around 2 to 3 times on startup. The error is in a small window called "stub" with the following message in it: Run-time error '9': Subscript out of range>>http://www.google.com/search?hl=en&q=s...mp;aq=f&oq=
It probably would not hurt if you do some general maintenance on XP...by running chkdsk and then defragging the system.
XP Chkdsk, Using the Graphical Version (My Computer) - http://www.updatexp.com/windows-xp-chkdsk.html
How to Understand and Use Chkdsk in Windows XP - http://vlaurie.com/computers2/Articles/chkdsk.htm