|It this a laptop or netbook or a desktop computer ?|
What is it's make and model ?
"Cannot use cd (tried using BIOS to re-order devices, no avail) "
You need to tell us more about what you tried, and what you saw on the screen.
The data on the hard drive has nothing to do with whether you can boot the computer from a bootable CD or DVD.
The CD or DVD MUST be bootable - does it boot on another computer ?
"Rebooted, got to black screen to select safe mode etc. and when i tired, would load up yo "MUP.SYS" and hang/restart"
If you're not familiar with Safe mode (without networking), when it works properly, you see a screen filled with lines that show which programs are loading, then it stays that way for the last screenfull for as long as a minute or more, then the Logon screen appears with at least the built in Administrator user and your user listed, you pick a user, then the desktop screen loads, a large window pops up and you are asked if you want to run the computer in Safe mode or choose something else. (Whatever you choose, you can run System Restore to load a previous restore point.)
If something is wrong with Windows, that may not work properly.
- If you WAIT longer when you see the last screen full of lines, Safe mode MAY proceed from there fine.
- The computer freezing forever at the screen filled with lines that show which programs are loading doesn't necessarily indicate the last line listed on the screen is loading the program that's is causing your problem with Safe mode, but something is definitely wrong with Windows.
"....system slower than normal. Booted up normally but slowly. started having probs with loading drivers. Started hanging at "found new hardware, ethernet controller....".
"Did a search of system, noticed some files were no longer available and internet stopped workingh..Rebooted, got to black screen to select safe mode etc. and when i tired, would load up yo "MUP.SYS" and hang/restart."
Your problems could all be caused by your hard drive having corruped data on it because it's the the process of failing.
If it IS in the process of failing, you need to get another hard drive FIRST before you do anything else, otherwise you're wasting your time trying to fix what can't be completely fixed.
If you have a desktop computer....
It is common to un-intentionally damage IDE data cables, especially while removing them - the 80 wire ones are more likely to be damaged. What usually happens is the cable is ripped at either edge and the wires there are either damaged or severed, often right at a connector or under it's cable clamp there, where it's hard to see - if a wire is severed but it's ends are touching, the connection is intermittent, rather than being reliable.
Another common thing is for the data cable to be separated from the connector contacts a bit after you have removed a cable - there should be no gap between the data cable and the connector - if there is press the cable against the connector to eliminate the gap.
80 wire data cables are also easily damaged at either edge if the cable is sharply creased at a fold in the cable.
Try another data cable if in doubt.
80 wire data cables must have the proper end connector connected to the mboard IDE header - usually that's blue, but in any case it's the one farther from the middle connector on a 3 connector data cable.
Check your SATA data cables. The connector on each end should "latch" into the socket on the drive and on the mboard, or on the drive controller card - it should not move when you merely brush your hand against it near the socket - if it does, mere vibration can cause a poor connection of it - use another SATA data cable that does "latch", or tape the connector in place.
(There is a slight projection or bump on one side of the outside of the connector that "latches" it into the socket - it's easily broken off or damaged)
The same thing applies for the SATA power connection.
If the data cables are okay, or if you have a laptop or netbook.....
Seagate's Seatools will test (almost) any brand of hard drive.
Do the long test.
The bootable Dos versions of SeaTools can be used even if Windows is not working properly.
If the hard drive itself tests okay, any data problems found can be fixed, one way or another.