Another disk boot failure victim in need of help

I'm running Windows XP on a Compaq 6000 series PC that I've had for about 4+ years. Had not a single problem as late as last Thursday night. The computer has been off ever since. I turned it on for the first time since then, around 7pm ET tonight 8/26/08 and I get this disk boot failure, insert system disk thing..I cannot for the life of me understand how a fully working PC suddenly displays this problem after not having even been used almost 5 days. I ran the system disk, selected setting up Windows XP, agreed to the legal statement. Then it was checking something and this is what it displayed along the bottom:
58644MB Disk 0 at Id 0 on bus 0 at atapi.
The next screen offers a choice to set up selected partition in unpartioned space or Delete selected partition. Below that is a box that states:
58644MB Disk 0 at Id 0 on bus 0 on atapi (setup cannot access this disk)
I tried both options regarding partitions and the next screen is blue and said something like:
the process/windows has been halted so as not to damage the computer and if this is the first time seeing the error message, reboot...then they give you other options if this has appeared already.
At the bottom of this page:
Technical info:
Stop: 0x0000008E (0x0000005, 0xF9E3DC13, 0xF9A0B7E4, 0x00000000)
setupdd.sys - Address F9E3DC13 base at F9E11000, DateStamp 41107c8f
Any ideas why this would happen now? I've read other posts from those with the same issue, but none of the fixes mentioned, that I've tried, has solved the problem. Also, I'm not comfortable opening the tower up to check the internal wiring.
Any theories or suggestions are welcome. I'm really pissed off about this.
Thanks