|Regarding Response 3, 4, 5|
I frequently have problems with my ADSL internet connection. My phone line is on poles in the alley - it was probably installed in 1959, and as far as I know it hasn't been replaced since, at least not the line on the poles.
We did have the phone line between the house and the nearest pole replaced twice in recent years - the first time when a tree we were taking down fell on it, the second time when a power lineman snagged it in the alley with his extended man bucket.
It is presently un-seasonably cold (up to ~25 C below average) where I am in Canada, and I often have problems with the ADSL connection more often in that case.
Around the time I was making response 13 the connection was terrible, so I re-set the power to my modem - it's leds did not show it had a good ADSL connection after that for quite a while.
I was probably having lesser connection problems earlier in the day.
For whatever reason, even when the ADSL connection is okay, direct links to large pdfs often never finish loading, but I can go to where the pdf download link is and RIGHT click it and choose Save as.... and download it in a short time, no problem.
I tried loading the pdf link you provided in response 4 just now - it STILL never finishes loading.
Using your info in response 6, I found
Dell™ Dimension™ XPS Rxxx Systems
Documentation: Dell™ Dimension™ XPS Rxxx Systems
I downloaded the Service manual and looked at page 55.
(Primary Hard-Drive mounting and removal instructions)
It appears the two long screws are supposed to already be there - you take them out when you want to remove the drive, or install a drive, replace them when the drive is in place, card side of the drive towards the outside of the case.
If the two screws are not there, see response 10.