I'm a Mac user but use a Dell PC laptop (Windows 7) for testing. Recently it slowed right down and when I tried to run the Maintenance Wizard I got the error code 0x80080005.
I could no longer get online with the Dell and troubleshooting the internet connection gave me the same "unexpected" error, so I looked it up on the Mac. Apparently the code meant I had a system-level problem. I ended up downloading a program called "Errorend" and then transferred it to the PC laptop. It took ages to launch the program as the laptop was really on its last legs, but it did launch eventually. It scanned my laptop, found almost 300 errors in the file structure, and then asked me to go online and buy the program in order to fix the errors...
Yeah, right. Sounds like a con, but I managed to get online again with the Dell (by resetting the router) and paid for the program's license. Lo and behold, the wee beasty worked just fine after letting Errorend do its stuff. Cost me less than thirty quid. My Dell is functioning normally again and that's well worth the spend.
There are many articles online which suggest that Errorend is a scam. Well, it worked for me!