I had a similar prob few weeks ago, desktop would load and then take forever to load something or just stay on the hour glass.
It took me 14 hours to fix (Im no tech) by scouring net for solutions on my phone.
Basically took three programs (one free, one free 14 day trial, one $10), now pc works fine
First, run in safe mode
and download, install and run
CCLeaner - FREE
http://www.piriform.com/ccleaner
Then I did the same for Superantispyware - free edition is trial
http://www.superantispyware.com/
My PC then started to work much better but after a day or two would stuff up again, I defraged and all that through windows and didnt make any diff.
I then downloaded the FREE scan from
http://www.speedypc.com/
and saw a whole bunch of stuff as issues.... Now usually there Scans are more SCAMS and they show a bunch of stuff thats not there to get you to buy program. This is not like that as I made sure I did my research before hand. I also defraged through SpeedyPC and unlike doing it through windows it seemed to actually work - don't ask why, not sure.
I am in no way affiliated with any of these programs, I receive no $$$ if you decide use them, they worked for my computer and saved me a lot of $$$ as I was just gonna buya new PC, they may not work for you but man if this wasn't the best $10 I ever spent I don't know what is.... Like I said it took me 14+ hours of trial and error and research over about 3-4 days and tha doesn't include the hours some of the scans took and If I had this info I would have been done in a few hours