Hi Milton,
Your 1603 Error is very likely an installer error which can happen when FSX is re-installed. Even though the usual error codes are 1605, 1607, 1622, 1628 and 1722, it may well be that 1603 is a part of that group.
My suggestion is to go to this link: resetsldl.exe
and download the software licencing tool reset package (the MS link has been dead for many years). Follow the instructions but bear in mind that when you come to the part to open Command Prompt, then use Command Prompt (Admin).
As well, after the reset has taken place, reboot your computer. These two instructions are not in the readme file in the reset package.
Then attempt to reinstall FSX and see if this works. And before you install Service Packs 1 and 2, run FSX in any flight first and check that everything is working as it should. Then after you install SP1, again take a flight
so that the SP1 files are located and activated properly. Then install SP2.
BTW, your log book problems are very likely because of a corrupt logbook. There are options for this, but if you are installing FSX, then the logbook problem will be fixed. I don't use the logbook for this reason and keep
my logs on a spreadsheet (deleting log book entries in the FSX logbook after each flight).
Let us know how you go and if you have any other problems.
Chris