Battery Charging Port and the Card Reader

I've has this computer for just about 2 years now, and I'm running into some problems.

1) A few months after my year warrantee expired, the AC port on my 710m lap top stopped working.  Since I have had it soldered three times, and I am again at the place where I must twist and maneuver the cord to get my computer to charge.  So I've been told that I need a new motherboard.   Can I only purchase the new motherboard from Dell? Or are there generic versions or cheaper websites? Also between the part and labor its going to end up costing me at least 450, so should I just buy another cheap computer instead of repairing this one?  Honestly I use this computer for the internet, word processing and other office applications, and to watch the occasional movie from netflix.  Please don't reply "its up to you." I know it is, I just need input, and I am not technology savvy.

2) Last time I went to load my pictures from my camera onto my computer using the SD card reader, which I have done before, it said that I needed to format it, which is weird because as I said I had done it many times before.  I didn't do it because I was scared to lose my pictures.  Anyway I had the transfer cable that came with my camera, so I just used that and didn't think much about it.  Tonight I tried to open a different SD micro card, and again it said it needed to be formatted.  I didn't care much what was on this card which I had also previously used, so I said OK.  Then my computer said that it could not be formatted.  I tried again, restarted my computer and tried again, all with no luck. Are my memory cards bad or my card reader? Is there anything I can do?

Thanks to all in advance for your help :)