Heya,

I had to rebuild a puter. I lost my BOINC. It's now back online and running, but is there a way to merge my new host and old host together?

No biggie.

If the descriptions of the pre- and post-rebuilds are different, I think it's very unlikely, particularly if you've changed the CPU and/or mobo. It will be detected as a different computer now. The only thing to do is to look at your project web pages for this/these computer/s and see whether 'Merge this computer' at the bottom of the pages offers another computer record to merge with.