Noone can deny my PC has had a lot of problems. Easy to understand since I had to format it 5 times during last year.
Having installed a number of airplanes in my FS2002, modified .cfg files and combine panels (main panel with side views) you understand re-installing my FS is not an easy task not to mention PAI, voice callsigns.
So if you face a similar situation you can keep a copy of your whole FS2002 directory somewhere else. I have an external USB disk but a DVD could also do if you keep it small. Once your system, is formatted re-install FS2002 from your original CDs. This will create a clean (no addons) FS2002 directory as it was the first time you installed FS. Now for the final step, replace the clean FS2002 directory with the one you backed up.
It may sound like no secret to many members here but for the rest it can be a good help and it will work 100% (I have done it 4 times). Even modules like FSNav, FSUIPC will work perfectly.