If the PC works, and you can save files, it is unlikely that you have a
partition problem. Partiton problem usually result is windows not seeing a
partition, or data being corrupted.
Your problem could be as simple as a badly fragmented partition, or possibly
some problem with the fiel system.
First, run CHKDSK C: /R (or whatever partition letter if not C

. Do this
in a command prompt. Say yes when it asks whether you want to do this
during a reboot. Reboot. e patient, the /R option is very slow. You might
want to do this for all partitions, just to be safe.
Next run a defragger. This is done from windows explorer, but
right-clicking on the disk letter, properties, tools, defrag. It is
important to run CHKDSK first, since defragging a disk with some problem can
create more problems.
Finally, what is your CPU and bus speed and drive speed for that matter? An
older PC can only move data so fast, and a hard drive will automatically
dumb-down to the fastest speed that the bus can handle.