VS 2010 want to see a grown man cry..errors after changing framework 4.0 to 3.5

Long story short a few weeks ago my pc crashed and I lost my entire project. I have spent every spare minute getting back to where I left off.
I the last 2 days I have been working on crystal report using project datasets. I was running into an issue and it was suggested I change my framework version to 3.5 which I did. Now I have over 100 errors. Most appear to be related to table adapters or table adapter managers.

Is there anyway to recover from that?

Thanks

LB