Hi u2. I think 55deg for the cpu is on the high side, but not disastrously so. I prefer the temperature to be below 50deg. You need an air flow across the motherboard, and particularly across the processor heat sink. The case air is usually blown out of the case back, and sucked in at the front. If reversing your case side fan helps then do it, but it may simply create an air flow short circuit. Check that there are no obstructions to air flowing over the processor heat sink, and that there is a free flow of cool air available to the fans. If you have a very fast processor, you may fing that you need a better processor heat sink.
I cant answer your question about using Partition Magic, but if you want to boot to a floppy (or cd) and instead the computer boots up normally, your BIOS is probably set to boot first to the C drive, you need to go into BIOS and set the first boot device to whatever you are trying to boot from.
I have partitioned my 40G hard drive to give me 9G C: drive for all my installed programs, 24G D: drive for saved files and 6G E: drive for backups of the C: drive. I do this so that if Windows gets severely corrupted, I can reformat the C: drive and restore it from E: without losing my saved files. I periodically copy the contents of D: to cd.
You can reinstall Windows over itself, but depending on what the problem is, this may not help. Reformatting and reinstalling is the only way to guarantee that none of the problems remain.