Windows 7 loading all profile is very slow

I would suggest trying to boot into safe mode, if thats still slow then try doing a virus scan with one of the many free programs (get the rescue cd or whatever they like to call it and use that) (Avira, Malware Bytes, etc)

If that turns up absolutely nothing then I suggest just moving your important files to somewhere not on that hard drive and reformatting.

Assuming the pc wasn't slow when you got it.