windows 7 wont load to log in screen

My HP pravillion elite hpe-230f computer was getting really slow and i ended most of the processes and it was fine then the next day it got slow again and it stopped responding. i restarted the computer two times and on the second time it got stuck on the log in screen before it loaded the opptions to choose who to log into. it says welcome and it stops loading i was wondering if i re-installed windows 7 if it would fix it and if it would if it would wipe my hard drive.

You run the repair option from the W7 install disks rather than a complete reinstall (you should see it in the corner once you get to the install menu).

Once you do get in you should run anti-virus software, like Malwarebytes, to make sure that is not what is slowing you down and then you might run a good cleaner, like CCleaner, to clear out your cache etc. Links to Malwarebytes and CCleaner are available in our Freeware DB.